[clang] [clang] Introduce `SemaCUDA` (PR #88559)

[Vlad Serebrennikov via cfe-commits]

Endilll wrote:

> Have you run the CUDA / HIP tests in the external test suite or anything?

No, just `check-clang` target. You think it's necessary to run something else before merging? If so, you should point me out to what to run, and preferably give some instructions, as CUDA development is completely foreign to me. Another option is to land and watch out for CUDA bots. I saw we have some, but not sure if they are in a good state.

https://github.com/llvm/llvm-project/pull/88559