[clang] [clang][AMDGPU] Clean-up handling of named barrier type (PR #207687)

[Yaxun Liu via cfe-commits]

yxsamliu wrote:

Maybe the aux-target coverage should live only in the HIP test.

This is testing the single-source host pass with an AMDGPU aux target, which is a HIP/CUDA compilation model. Since the type and rules here are AMDGPU-specific, `SemaHIP/amdgpu-barrier.hip` seems like the right place.

I would keep `SemaCXX` and `SemaOpenCL` to AMDGPU primary-triple coverage and drop their aux-target RUN lines.

https://github.com/llvm/llvm-project/pull/207687