[llvm] llvm-reduce: Filter function based on uses before removing arguments (PR #133412)

[Matt Arsenault via llvm-commits]

arsenm wrote:

### Merge activity

* **Mar 28, 1:01 PM EDT**: A user merged this pull request with [Graphite](https://app.graphite.dev/github/pr/llvm/llvm-project/133412).


https://github.com/llvm/llvm-project/pull/133412