[clang] [clang] Refactor Builtins.def to be a tablegen file (PR #68324)

[Nikolas Klauser via cfe-commits]

philnik777 wrote:

Not right now. I think the first thing to do is moving all the builtins to tablegen before we can make better use of it, which is going to take a while.


https://github.com/llvm/llvm-project/pull/68324