[mlir][memref] Fix crash in SubViewReturnTypeCanonicalizer

`SubViewReturnTypeCanonicalizer` is used by `OpWithOffsetSizesAndStridesConstantArgumentFolder`, which folds constant SSA value (dynamic) sizes into static sizes. The previous implementation crashed when a dynamic size was folded into a static `1` dimension, which was then mistaken as a rank reduction.

Differential Revision: https://reviews.llvm.org/D158721