[clang] [clang-cl] [AST] Reapply #102848 Fix placeholder return type name mangling for MSVC 1920+ / VS2019+ (PR #104722)

[Max Winkler via cfe-commits]

MaxEW707 wrote:

@zmodem

I have a fix for https://ci.chromium.org/ui/p/chromium/builders/ci/ToTWin.

This was an accidental regression on my part, sorry.

The fix is here https://github.com/llvm/llvm-project/pull/105999.

https://github.com/llvm/llvm-project/pull/104722