Rollup merge of #112300 - Zalathar:run-coverage, r=wesleywiser

Convert `run-make/coverage-reports` tests to use a custom compiletest mode

I was frustrated by the fact that most of the coverage tests are glued together with makefiles and shell scripts, so I tried my hand at converting most of them over to a newly-implemented `run-coverage` mode/suite in compiletest.

This ~~*mostly*~~ resolves #85009, ~~though I've left a small number of the existing tests as-is because they would require more work to fix/support~~.

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I had time to go back and add support for the more troublesome tests that I had initially skipped over, so this PR now manages to completely get rid of `run-make/coverage-reports`.

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The patches are arranged as follows:

- Declare the new mode/suite in bootstrap
- Small changes to compiletest that will be used by the new mode
- Implement the new mode in compiletest
- Migrate most of the tests over
- Add more code to bootstrap and compiletest to support the remaining tests
- Migrate the remaining tests (with some temporary hacks to avoid re-blessing them)
- Remove the temporary hacks and re-bless the migrated tests
- Remove the unused remnants of `run-make/coverage-reports`

1 files changed, 34 insertions, 0 deletions

diff --git a/tests/run-coverage/assert.coverage b/tests/run-coverage/assert.coverage
new file mode 100644
index 00000000000..a7134a149e2
--- /dev/null
+++ b/tests/run-coverage/assert.coverage
@@ -0,0 +1,34 @@
+    1|       |#![allow(unused_assignments)]
+    2|       |// failure-status: 101
+    3|       |
+    4|      4|fn might_fail_assert(one_plus_one: u32) {
+    5|      4|    println!("does 1 + 1 = {}?", one_plus_one);
+    6|      4|    assert_eq!(1 + 1, one_plus_one, "the argument was wrong");
+                                                  ^1
+    7|      3|}
+    8|       |
+    9|      1|fn main() -> Result<(),u8> {
+   10|      1|    let mut countdown = 10;
+   11|     11|    while countdown > 0 {
+   12|     11|        if countdown == 1 {
+   13|      1|            might_fail_assert(3);
+   14|     10|        } else if countdown < 5 {
+   15|      3|            might_fail_assert(2);
+   16|      6|        }
+   17|     10|        countdown -= 1;
+   18|       |    }
+   19|      0|    Ok(())
+   20|      0|}
+   21|       |
+   22|       |// Notes:
+   23|       |//   1. Compare this program and its coverage results to those of the very similar test
+   24|       |//      `panic_unwind.rs`, and similar tests `abort.rs` and `try_error_result.rs`.
+   25|       |//   2. This test confirms the coverage generated when a program passes or fails an `assert!()` or
+   26|       |//      related `assert_*!()` macro.
+   27|       |//   3. Notably, the `assert` macros *do not* generate `TerminatorKind::Assert`. The macros produce
+   28|       |//      conditional expressions, `TerminatorKind::SwitchInt` branches, and a possible call to
+   29|       |//      `begin_panic_fmt()` (that begins a panic unwind, if the assertion test fails).
+   30|       |//   4. `TerminatoKind::Assert` is, however, also present in the MIR generated for this test
+   31|       |//      (and in many other coverage tests). The `Assert` terminator is typically generated by the
+   32|       |//      Rust compiler to check for runtime failures, such as numeric overflows.
+