[mlir] [MLIR][Linalg] Add aggregate ops decomposition pass and softmax decom… (PR #97582)

[Andrzej Warzyński]

banach-space wrote:

> Do I understand correctly that you suggest having a single lit with the body of @softmax, the transformation IR, and runs both the decomposition via the pass and transform interpreter?

Yes, something along those lines. Basically, IMO, we should identify a canonical way to test transformations with both "passes" and TD so that we maximise "test case" re-use. 

https://github.com/llvm/llvm-project/pull/97582