Don't use new-llvm-pass-manager=no in test

Author: nikic

src/test/codegen/panic-in-drop-abort.rs

@@ -1,10 +1,12 @@
-// compile-flags: -Z panic-in-drop=abort -O -Z new-llvm-pass-manager=no
+// compile-flags: -Z panic-in-drop=abort -O
+// ignore-msvc
 
 // Ensure that unwinding code paths are eliminated from the output after
 // optimization.
 
-// This test uses -Z new-llvm-pass-manager=no, because the expected optimization does not happen
-// on targets using SEH exceptions (i.e. MSVC) anymore. The core issue is that Rust promises that
+// This test uses ignore-msvc, because the expected optimization does not happen on targets using
+// SEH exceptions with the new LLVM pass manager anymore, see
+// https://github.com/llvm/llvm-project/issues/51311. The core issue is that Rust promises that
 // the drop_in_place() function can't unwind, but implements it in a way that *can*, because we
 // currently go out of our way to allow longjmps, which also use the unwinding mechanism on MSVC
 // targets. We should either forbid longjmps, or not assume nounwind, making this optimization