[clang] [X86][Clang] allow CRC32 intrinsics to be used in constexp (PR #173908)

[Simon Pilgrim via cfe-commits]

https://github.com/RKSimon requested changes to this pull request.

Please can you investigate the _mm_crc32_u32 failures? I might have gotten the fuzz test wrong but we need to confirm on hw

https://github.com/llvm/llvm-project/pull/173908