[llvm] [OFFLOAD] Add plugin with support for Intel oneAPI Level Zero (PR #158900)

[Joseph Huber via llvm-commits]

jhuber6 wrote:

> > By the way unless this passes all the existing tests it should be disabled by default.
> 
> There's no testing in this PR.

It probably doesn't enable it as a backend for the OpenMP tests, but I'd imagine it would show up in platform detection for the offloading ones.

https://github.com/llvm/llvm-project/pull/158900