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

[Shilei Tian via cfe-commits]

https://github.com/shiltian approved this pull request.

it seems like there are some test failures but I think the PR looks good

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