Add syntactic sugar for strided memref parsing.

Add syntactic sugar for strided memref parsing.
This CL implements the last remaining bit of the [strided memref proposal](https://groups.google.com/a/tensorflow.org/forum/#!topic/mlir/MaL8m2nXuio).

The syntax is a bit more explicit than what was originally proposed and resembles:
  `memref<?x?xf32, offset: 0 strides: [?, 1]>`

Nonnegative strides and offsets are currently supported. Future extensions will include negative strides.

This also gives a concrete example of syntactic sugar for the ([RFC] Proposed Changes to MemRef and Tensor MLIR Types)[https://groups.google.com/a/tensorflow.org/forum/#!topic/mlir/-wKHANzDNTg].

The underlying implementation still uses AffineMap layout.

PiperOrigin-RevId: 272717437