[llvm] [mlir] [mlir][Interfaces][NFC] Add TableGen test op for value bounds tests (PR #88717)

[Benjamin Maxwell via llvm-commits]

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

LGTM, seems like a decent improvement. 
I'd maybe make enums for the bound/comparator, though I think a `StrAttr` is fine for test ops.    

https://github.com/llvm/llvm-project/pull/88717