[mlir][linalg] Make Linalg vectorizer lower affine.apply
It is possible that the input to the Linalg vectorizer contains
`affine.apply` ops (see the example in [1]). Such operations are not
vectarizable at the moment, but this can be fixed by simply converting
them to arithmetic operations. This is basically what this patch
introduces.
The IR change enabled in this patch could be part of a larger set of
"linalgOp pre-processing" transformations that happens right before
vectorization starts but after we know we can vectorize the op. I am
leaving this as a TODO.
[1] https://github.com/iree-org/iree/issues/10876.
Differential Revision: https://reviews.llvm.org/D142371