[mlir][affine] Support affine.parallel in the index set analysis

Support affine.parallel in the index set analysis. It allows us to do dependence analysis containing affine.parallel in addition to affine.for and affine.if. This change only supports the constant lower/upper bound in affine.parallel. Other complicated affine map bounds will be supported in further commits.

See https://github.com/llvm/llvm-project/issues/57327

Reviewed By: bondhugula

Differential Revision: https://reviews.llvm.org/D136056