[clang] Bulk port 64-bit x86 builtins to TableGen (PR #121043)

[Chandler Carruth via cfe-commits]

chandlerc wrote:

I've put the script in a gist here: https://gist.github.com/chandlerc/de807ea073beac351f87c660e1d4b7a0

X-macros: the `BUILTIN(...)` macro invocations in an included file, where the includer defines those macros to a specific pattern. https://en.wikipedia.org/wiki/X_macro LLVM uses a somewhat odd form that involves an include instead of expanding a define, but its the best name I know of for the technique.

Working on merging the base, and then will rebase this with the improvements from that.

https://github.com/llvm/llvm-project/pull/121043