[clang] [OpenMP][clang][HIP][CUDA] fix weak alias emit on device compilation (PR #164326)

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Jason-VanBeusekom wrote:

amdgcn_weak_alias.c was failing on the reverse iteration runs due to metadata checks, I removed them and it is now passing on my local build, I created https://github.com/llvm/llvm-project/pull/170326 with this change.

https://github.com/llvm/llvm-project/pull/164326