[llvm] [Offload][OMPX] Add the runtime support for multi-dim grid and block (PR #118042)

[Johannes Doerfert via llvm-commits]

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

LG, fix the test.
Consider not printing dim 2 and 3 if we run in OpenMP mode, but OK for now.

https://github.com/llvm/llvm-project/pull/118042