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

[Alex Duran via llvm-commits]

adurang wrote:

> How well does this pass the unit tests?

This is the current status:

```
Total Discovered Tests: 393
  Unsupported      : 190 (48.35%)
  Passed           :  31 (7.89%)
  Expectedly Failed:  14 (3.56%)
  Failed           : 158 (40.20%)
```

But this is to be expected given than most other pieces for spirv are not yet complete (e.g., frontend) or not there at all (e.g., device library).


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