[llvm] [mlir] [OMPIRBuilder] Don't outline DISTRIBUTE on CPUs (PR #158317)

[Tom Eccles via llvm-commits]

tblah wrote:

```
 Failed Tests (2):
    lldb-api :: commands/expression/import-std-module/vector-dbg-info-content/TestDbgInfoContentVectorFromStdModule.py
    lldb-api :: commands/expression/import-std-module/vector-of-vectors/TestVectorOfVectorsFromStdModule.py
```

Doesn't look related.

https://github.com/llvm/llvm-project/pull/158317