[clang] [llvm] [openmp] [OpenMP] Use generic IR for the OpenMP DeviceRTL (PR #119091)

[Joseph Huber via cfe-commits]

jhuber6 wrote:

> This probably should retain separate wave32/wave64 builds. Additionally, should have extension points for subtarget specific implementations

That's what Shilei was talking about since we have `__nvvm_reflect` for that for NVPTX.

https://github.com/llvm/llvm-project/pull/119091