[llvm] [ConstraintElim] Add pre-commit tests for PR82271. NFC. (PR #82357)

[Florian Hahn via llvm-commits]

https://github.com/fhahn approved this pull request.

Thanks for splitting this off! Suggestion for a few additions test variants inline.

LGTM, with the extra variants added.

https://github.com/llvm/llvm-project/pull/82357