[clang] [llvm] [Clang][AIX] Add -mloadtime-comment-vars flag to preserve identifying variables (PR #187986)

[Hubert Tong via cfe-commits]

https://github.com/hubert-reinterpretcast commented:

Finished reviewing the code except for the C++ CodeGen test. Open comment threads still to be verified.

https://github.com/llvm/llvm-project/pull/187986