[mlir] Add offset/stride helper functions to OffsetSizeAndStrideOpInterface

[mlir] Add offset/stride helper functions to OffsetSizeAndStrideOpInterface

* Add hasUnitStride and hasZeroOffset to OffsetSizeAndStrideOpInterface. These functions are useful for various patterns. E.g., some vectorization patterns apply only for tensor ops with zero offsets and/or unit stride.
* Add getConstantIntValue and isEqualConstantInt helper functions, which are useful for implementing the two above functions, as well as various patterns.

Differential Revision: https://reviews.llvm.org/D103763