[clang] [Headers][X86] Allow SLLDQ/SRLDQ byte shift intrinsics to be used in constexpr (PR #164166)

[Ye Tian via cfe-commits]

TianYe717 wrote:

> unifying the implementation and doing different
Done, thanks! I unified the implementation and used lambda expressions to handle the differences


https://github.com/llvm/llvm-project/pull/164166