[llvm] [Dexter] Add label nodes for line references (PR #202544)

[via llvm-commits]

graphite-app[bot] wrote:

### Merge activity

* **Jun 15, 12:34 PM UTC**: `SLTozer` 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/202544