[clang] [CIR][AMDGPU][SPIR-V] Support metadata intrinsic args for feature predicates (PR #229330)

[Arseniy Obolenskiy via cfe-commits]

aobolensk wrote:

> There's really no getting around the fact that intrinsics, especially target intrinsics, are going to be very low level. However, declaring that something is metadata is really an LLVM IR implementation detail. We don't have metadata as such in CIR, and I'd like to keep it that way.

Thanks for the feedback, I have reworked that. Could you please take a look?

https://github.com/llvm/llvm-project/pull/229330