Fix `--nocapture` for run-make tests

This was confusing because there are three layers of output hiding.
1. libtest shoves all output into a buffer and does not print it unless the test fails or `--nocapture` is passed.
2. compiletest chooses whether to print the output from any given process.
3. run-make-support chooses what output to print.

This modifies 2 and 3.

- compiletest: Don't require both `--verbose` and `--nocapture` to show the output of run-make tests.
- compiletest: Distinguish rustc and rmake stderr by printing the command name (e.g. "--stderr--" to "--rustc stderr--").
- run-make-support: Unconditionally print the needle/haystack being searched. Previously this was only printed on failure.

Before:
```
$ x t tests/run-make/linker-warning --force-rerun -- --nocapture
running 1 tests
.

test result: ok. 1 passed; 0 failed; 0 ignored; 0 measured; 377 filtered out; finished in 281.64ms
$ x t tests/run-make/linker-warning --force-rerun -v -- --nocapture 2>&1 | wc -l
1004
$ x t tests/run-make/linker-warning --force-rerun -v -- --nocapture | tail -n40
running 1 tests

------stdout------------------------------

------stderr------------------------------
warning: unused import: `std::path::Path`
 --> /home/jyn/src/rust2/tests/run-make/linker-warning/rmake.rs:1:5
  |
1 | use std::path::Path;
  |     ^^^^^^^^^^^^^^^
  |
  = note: `#[warn(unused_imports)]` on by default

warning: unused import: `run_make_support::rfs::remove_file`
 --> /home/jyn/src/rust2/tests/run-make/linker-warning/rmake.rs:3:5
  |
3 | use run_make_support::rfs::remove_file;
  |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

warning: 2 warnings emitted

------------------------------------------
test [run-make] tests/run-make/linker-warning ... ok

test result: ok. 1 passed; 0 failed; 0 ignored; 0 measured; 377 filtered out; finished in 285.89ms
```

After:

```
Testing stage1 compiletest suite=run-make mode=run-make (x86_64-unknown-linux-gnu)

running 1 tests
------rmake stdout------------------------------

------rmake stderr------------------------------
assert_contains_regex:
=== HAYSTACK ===
error: linking with `./fake-linker` failed: exit status: 1
  |
  = note: LC_ALL="C" PATH="/home/jyn/src/rust2/build/x86_64-unknown-linux-gnu/stage1/lib/rustlib/x86_64-unknown-linux-gnu/bin:...:/bin" VSLANG="1033" "./fake-linker" "-m64" "/tmp/rustcYqdAZT/symbols.o" "main.main.d17f5fbe6225cf88-cgu.0.rcgu.o" "main.2uoctswmurc6ir5rvoay0p9ke.rcgu.o" "-Wl,--as-needed" "-Wl,-Bstatic" "-Wl,-Bdynamic" "-lgcc_s" "-lutil" "-lrt" "-lpthread" "-lm" "-ldl" "-lc" "-B/home/jyn/src/rust2/build/x86_64-unknown-linux-gnu/stage1/lib/rustlib/x86_64-unknown-linux-gnu/bin/gcc-ld" "-fuse-ld=lld" "-Wl,--eh-frame-hdr" "-Wl,-z,noexecstack" "-L" "/home/jyn/src/rust2/build/x86_64-unknown-linux-gnu/test/run-make/linker-warning/rmake_out" "-L" "/home/jyn/src/rust2/build/x86_64-unknown-linux-gnu/stage1/lib/rustlib/x86_64-unknown-linux-gnu/lib" "-o" "main" "-Wl,--gc-sections" "-pie" "-Wl,-z,relro,-z,now" "-nodefaultlibs" "run_make_error"
  = note: error: baz

error: aborting due to 1 previous error

=== NEEDLE ===
fake-linker.*run_make_error
assert_not_contains_regex:
=== HAYSTACK ===

=== NEEDLE ===
fake-linker.*run_make_error

------------------------------------------
.

test result: ok. 1 passed; 0 failed; 0 ignored; 0 measured; 377 filtered out; finished in 314.81ms
```

3 files changed, 54 insertions, 55 deletions

diff --git a/src/tools/compiletest/src/runtest.rs b/src/tools/compiletest/src/runtest.rs
index 7b11bf3b121..4a4494a1e23 100644
--- a/src/tools/compiletest/src/runtest.rs
+++ b/src/tools/compiletest/src/runtest.rs
@@ -410,7 +410,12 @@ impl<'test> TestCx<'test> {
             truncated: Truncated::No,
             cmdline: format!("{cmd:?}"),
         };
-        self.dump_output(&proc_res.stdout, &proc_res.stderr);
+        self.dump_output(
+            self.config.verbose,
+            &cmd.get_program().to_string_lossy(),
+            &proc_res.stdout,
+            &proc_res.stderr,
+        );
 
         proc_res
     }
@@ -1401,7 +1406,12 @@ impl<'test> TestCx<'test> {
             cmdline,
         };
 
-        self.dump_output(&result.stdout, &result.stderr);
+        self.dump_output(
+            self.config.verbose,
+            &command.get_program().to_string_lossy(),
+            &result.stdout,
+            &result.stderr,
+        );
 
         result
     }
@@ -1816,12 +1826,22 @@ impl<'test> TestCx<'test> {
         }
     }
 
-    fn dump_output(&self, out: &str, err: &str) {
+    fn dump_output(&self, print_output: bool, proc_name: &str, out: &str, err: &str) {
         let revision = if let Some(r) = self.revision { format!("{}.", r) } else { String::new() };
 
         self.dump_output_file(out, &format!("{}out", revision));
         self.dump_output_file(err, &format!("{}err", revision));
-        self.maybe_dump_to_stdout(out, err);
+
+        if !print_output {
+            return;
+        }
+
+        let proc_name = Path::new(proc_name).file_name().unwrap().to_string_lossy();
+        println!("------{proc_name} stdout------------------------------");
+        println!("{}", out);
+        println!("------{proc_name} stderr------------------------------");
+        println!("{}", err);
+        println!("------------------------------------------");
     }
 
     fn dump_output_file(&self, out: &str, extension: &str) {
@@ -1874,16 +1894,6 @@ impl<'test> TestCx<'test> {
         output_base_name(self.config, self.testpaths, self.safe_revision())
     }
 
-    fn maybe_dump_to_stdout(&self, out: &str, err: &str) {
-        if self.config.verbose {
-            println!("------stdout------------------------------");
-            println!("{}", out);
-            println!("------stderr------------------------------");
-            println!("{}", err);
-            println!("------------------------------------------");
-        }
-    }
-
     fn error(&self, err: &str) {
         match self.revision {
             Some(rev) => println!("\nerror in revision `{}`: {}", rev, err),
diff --git a/src/tools/compiletest/src/runtest/run_make.rs b/src/tools/compiletest/src/runtest/run_make.rs
index 04bc2d7787d..85ade5b727a 100644
--- a/src/tools/compiletest/src/runtest/run_make.rs
+++ b/src/tools/compiletest/src/runtest/run_make.rs
@@ -517,14 +517,13 @@ impl TestCx<'_> {
 
         let proc = disable_error_reporting(|| cmd.spawn().expect("failed to spawn `rmake`"));
         let (Output { stdout, stderr, status }, truncated) = self.read2_abbreviated(proc);
+        let stdout = String::from_utf8_lossy(&stdout).into_owned();
+        let stderr = String::from_utf8_lossy(&stderr).into_owned();
+        // This conditions on `status.success()` so we don't print output twice on error.
+        // NOTE: this code is called from a libtest thread, so it's hidden by default unless --nocapture is passed.
+        self.dump_output(status.success(), &cmd.get_program().to_string_lossy(), &stdout, &stderr);
         if !status.success() {
-            let res = ProcRes {
-                status,
-                stdout: String::from_utf8_lossy(&stdout).into_owned(),
-                stderr: String::from_utf8_lossy(&stderr).into_owned(),
-                truncated,
-                cmdline: format!("{:?}", cmd),
-            };
+            let res = ProcRes { status, stdout, stderr, truncated, cmdline: format!("{:?}", cmd) };
             self.fatal_proc_rec("rmake recipe failed to complete", &res);
         }
     }
diff --git a/src/tools/run-make-support/src/assertion_helpers.rs b/src/tools/run-make-support/src/assertion_helpers.rs
index b4da65aff4a..e84a3cf633f 100644
--- a/src/tools/run-make-support/src/assertion_helpers.rs
+++ b/src/tools/run-make-support/src/assertion_helpers.rs
@@ -5,16 +5,31 @@ use std::path::Path;
 
 use crate::{fs, regex};
 
+fn print<'a, 'e, A: AsRef<str>, E: AsRef<str>>(
+    assertion_kind: &str,
+    haystack: &'a A,
+    needle: &'e E,
+) -> (&'a str, &'e str) {
+    let haystack = haystack.as_ref();
+    let needle = needle.as_ref();
+    eprintln!("{assertion_kind}:");
+    eprintln!("=== HAYSTACK ===");
+    eprintln!("{}", haystack);
+    eprintln!("=== NEEDLE ===");
+    eprintln!("{}", needle);
+    (haystack, needle)
+}
+
 /// Assert that `actual` is equal to `expected`.
 #[track_caller]
 pub fn assert_equals<A: AsRef<str>, E: AsRef<str>>(actual: A, expected: E) {
     let actual = actual.as_ref();
     let expected = expected.as_ref();
+    eprintln!("=== ACTUAL TEXT ===");
+    eprintln!("{}", actual);
+    eprintln!("=== EXPECTED ===");
+    eprintln!("{}", expected);
     if actual != expected {
-        eprintln!("=== ACTUAL TEXT ===");
-        eprintln!("{}", actual);
-        eprintln!("=== EXPECTED ===");
-        eprintln!("{}", expected);
         panic!("expected text was not found in actual text");
     }
 }
@@ -22,13 +37,8 @@ pub fn assert_equals<A: AsRef<str>, E: AsRef<str>>(actual: A, expected: E) {
 /// Assert that `haystack` contains `needle`.
 #[track_caller]
 pub fn assert_contains<H: AsRef<str>, N: AsRef<str>>(haystack: H, needle: N) {
-    let haystack = haystack.as_ref();
-    let needle = needle.as_ref();
+    let (haystack, needle) = print("assert_contains", &haystack, &needle);
     if !haystack.contains(needle) {
-        eprintln!("=== HAYSTACK ===");
-        eprintln!("{}", haystack);
-        eprintln!("=== NEEDLE ===");
-        eprintln!("{}", needle);
         panic!("needle was not found in haystack");
     }
 }
@@ -36,13 +46,8 @@ pub fn assert_contains<H: AsRef<str>, N: AsRef<str>>(haystack: H, needle: N) {
 /// Assert that `haystack` does not contain `needle`.
 #[track_caller]
 pub fn assert_not_contains<H: AsRef<str>, N: AsRef<str>>(haystack: H, needle: N) {
-    let haystack = haystack.as_ref();
-    let needle = needle.as_ref();
+    let (haystack, needle) = print("assert_not_contains", &haystack, &needle);
     if haystack.contains(needle) {
-        eprintln!("=== HAYSTACK ===");
-        eprintln!("{}", haystack);
-        eprintln!("=== NEEDLE ===");
-        eprintln!("{}", needle);
         panic!("needle was unexpectedly found in haystack");
     }
 }
@@ -50,14 +55,9 @@ pub fn assert_not_contains<H: AsRef<str>, N: AsRef<str>>(haystack: H, needle: N)
 /// Assert that `haystack` contains the regex pattern `needle`.
 #[track_caller]
 pub fn assert_contains_regex<H: AsRef<str>, N: AsRef<str>>(haystack: H, needle: N) {
-    let haystack = haystack.as_ref();
-    let needle = needle.as_ref();
+    let (haystack, needle) = print("assert_contains_regex", &haystack, &needle);
     let re = regex::Regex::new(needle).unwrap();
     if !re.is_match(haystack) {
-        eprintln!("=== HAYSTACK ===");
-        eprintln!("{}", haystack);
-        eprintln!("=== NEEDLE ===");
-        eprintln!("{}", needle);
         panic!("needle was not found in haystack");
     }
 }
@@ -65,14 +65,9 @@ pub fn assert_contains_regex<H: AsRef<str>, N: AsRef<str>>(haystack: H, needle:
 /// Assert that `haystack` does not contain the regex pattern `needle`.
 #[track_caller]
 pub fn assert_not_contains_regex<H: AsRef<str>, N: AsRef<str>>(haystack: H, needle: N) {
-    let haystack = haystack.as_ref();
-    let needle = needle.as_ref();
+    let (haystack, needle) = print("assert_not_contains_regex", &haystack, &needle);
     let re = regex::Regex::new(needle).unwrap();
     if re.is_match(haystack) {
-        eprintln!("=== HAYSTACK ===");
-        eprintln!("{}", haystack);
-        eprintln!("=== NEEDLE ===");
-        eprintln!("{}", needle);
         panic!("needle was unexpectedly found in haystack");
     }
 }
@@ -80,13 +75,8 @@ pub fn assert_not_contains_regex<H: AsRef<str>, N: AsRef<str>>(haystack: H, need
 /// Assert that `haystack` contains `needle` a `count` number of times.
 #[track_caller]
 pub fn assert_count_is<H: AsRef<str>, N: AsRef<str>>(count: usize, haystack: H, needle: N) {
-    let haystack = haystack.as_ref();
-    let needle = needle.as_ref();
+    let (haystack, needle) = print("assert_count_is", &haystack, &needle);
     if count != haystack.matches(needle).count() {
-        eprintln!("=== HAYSTACK ===");
-        eprintln!("{}", haystack);
-        eprintln!("=== NEEDLE ===");
-        eprintln!("{}", needle);
         panic!("needle did not appear {count} times in haystack");
     }
 }