[llvm] llvm-reduce: Increase operands-to-args test coverage (PR #133853)

[Matt Arsenault via llvm-commits]

arsenm wrote:

### Merge activity

* **Apr 2, 6:01 AM EDT**: A user started a stack merge that includes this pull request via [Graphite](https://app.graphite.dev/github/pr/llvm/llvm-project/133853).


https://github.com/llvm/llvm-project/pull/133853