[clang] [Clang] Start moving X86Builtins.def to X86Builtins.td (PR #106005)

[Aaron Ballman via cfe-commits]

https://github.com/AaronBallman commented:

I think this is a reasonable direction to go, so the changes notionally LGTM. And I didn't spot any issues with the conversion either, but I'd appreciate a second set of eyes more familiar with x86 builtins to double-check.

https://github.com/llvm/llvm-project/pull/106005