[clang] [CIR] Add math and builtin intrinsics support (PR #175233)

[Hendrik Hübner via cfe-commits]

https://github.com/HendrikHuebner commented:

Please submit smaller PRs in the future - its hard to review 3000 lines of code at once. I'd split this up into at least 3 smaller PRs personally.

https://github.com/llvm/llvm-project/pull/175233