[clang] [compiler-rt] [llvm] [PGO][AMDGPU] Add basic HIP offload PGO support (PR #177665)

[Yaxun Liu via cfe-commits]

yxsamliu wrote:

I will merge this PR for now. If any concerns came up, we can do post-commit review.

https://github.com/llvm/llvm-project/pull/177665