[mlir][affine][NFC] Extract core functionality of `canonicalizeMinMaxOp`

Move code from SCF to Affine: Add a new helper function `simplifyConstrainedMinMaxOp` to Affine/Analysis/Utils.h. `canonicalizeMinMaxOp` was originally designed for loop peeling, but it is not SCF-specific and can be used to simplify any affine.min/max ops.

Various functions in SCF/Transforms are simplified by dropping unnecessary parameters.

Differential Revision: https://reviews.llvm.org/D140962