[clang] [llvm] [BPF] Do atomic_fetch_*() pattern matching with memory ordering (PR #107343)

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eddyz87 wrote:

@yonghong-song, note: if all three commits remain a part of a single pull request, the are required to be squashed ([link](https://llvm.org/docs/GitHub.html)). If you want all three to be separate, each has to have it's separate pull request (one branch forked from another).

https://github.com/llvm/llvm-project/pull/107343