[llvm] [AMDGPU] Make globally-addressable-scratch opt-in (PR #189555)

[via llvm-commits]

graphite-app[bot] wrote:

### Merge activity

* **Jun 4, 7:37 AM UTC**: `Pierre-vh` added this pull request to the [Graphite merge queue](https://app.graphite.com/merges?org=llvm&repo=llvm-project).


https://github.com/llvm/llvm-project/pull/189555