[mlir][vector] Fix double rank reducing folding bug
In https://reviews.llvm.org/D133883, we changed the
`FoldExtractSliceIntoTransferRead` pattern from requiring
full identity map to minor identity map. This effectively
allows rank reducing `vector.transfer_read` ops. However,
the logic for checking `tensor.extract_slice` rank reducing
still looks at the vector rank, which now could be smaller
than the `tensor.extract_slice`'s output tensor rank.
It ends up we can have incorrect index cacluation after
folding due to this double rank reducing behavior.
Reviewed By: ThomasRaoux
Differential Revision: https://reviews.llvm.org/D134984