[clang] Let clang-cl support CUDA/HIP (PR #68921)

[Simon Tatham via cfe-commits]

statham-arm wrote:

@yxsamliu I've just raised https://github.com/llvm/llvm-project/pull/70055 which fixes an issue with the new test here. Perhaps it might also allow you to remove the exclusion for `system-darwin`?

https://github.com/llvm/llvm-project/pull/68921