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

[via cfe-commits]

ronlieb wrote:

> @ronlieb This will probably conflict a lot with downstream, should probably wait until I've talked it over with others before trying to merge it in AOMP.

yes please , lets wait until internal monday mtg to discuss. also i would like to help with some precommit performance testing   using a downstream build.

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