[clang] [llvm] [openmp] [offload][OpenMP] Remove device code for num_threads strict (PR #157893)

[Robert Imschweiler via llvm-commits]

ro-i wrote:

@tbaederr you added some test using num_threads strict (+message/severity) for target in https://github.com/llvm/llvm-project/commit/83ca87715974d386e1ffee8ae8797d8f0f1db205. Can we substitute this by something else?

https://github.com/llvm/llvm-project/pull/157893