[MLIR] Vectorize tensor.extract on 1-d tensor

This patch implements the vectorization of tensor.extract for the
basic 1-d lookup case. It only vectorizes the tensor.extract to a
vector.gather when the op extracts value from an 1-d tensor.

Related discussion: https://github.com/iree-org/iree/issues/9198

Reviewed By: dcaballe

Differential Revision: https://reviews.llvm.org/D133786