Don't pass -Z unstable-options by default for UI tests

- Pass it explicitly where appropriate
- Update stderr files and warnings; it turns that unstable-options has
  far-reaching effects on diagnostics.

1 files changed, 0 insertions, 1 deletions

diff --git a/src/bootstrap/test.rs b/src/bootstrap/test.rs
index cc7c143d474..1fa37737b55 100644
--- a/src/bootstrap/test.rs
+++ b/src/bootstrap/test.rs
@@ -1280,7 +1280,6 @@ note: if you're sure you want to do this, please open an issue as to why. In the
             }
         }
         flags.push(format!("-Cdebuginfo={}", builder.config.rust_debuginfo_level_tests));
-        flags.push("-Zunstable-options".to_string());
         flags.push(builder.config.cmd.rustc_args().join(" "));
 
         if let Some(linker) = builder.linker(target) {