[clang] [OpenMP] Allow GPUs to be targeted directly via `-fopenmp`. (PR #122149)

[Shilei Tian via cfe-commits]

https://github.com/shiltian commented:

Do we have a clear idea on if a construct can behave in a different manner if it is nested in a target region?

https://github.com/llvm/llvm-project/pull/122149