[llvm] [openmp] [Offload][OMPT][NFCI] Call ompt_libomp_connect instead of dlopen libomp (PR #214556)

[Michael Halkenhäuser via llvm-commits]

mhalk wrote:

> Is some downstream implementation using liboffload with a different OpenMP runtime?
IDK for sure, but to the best of my knowledge I'd say: No, w.r.t. ROCm.

Thanks for the feedback and approvals :)

https://github.com/llvm/llvm-project/pull/214556