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

[via llvm-commits]

ronlieb wrote:

> > Out of curiosity: Have you looked at how this applies downstream?
> 
> No, I didn't.

in hindsight, i wish you had

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