[mlir] [VectorOps] Rewriting of vector.extract/insert_slices to other vector ops

Summary:
Rewrites the extract/insert_slices operation in terms of
strided_slice/insert_strided_slice ops with intermediate
tuple uses (that should get optimimized away with typical
usage). This is done in a separate "pass" to enable testing
this particular rewriting in isolation.

Reviewers: nicolasvasilache, andydavis1, ftynse

Reviewed By: nicolasvasilache

Subscribers: merge_guards_bot, mehdi_amini, rriddle, jpienaar, burmako, shauheen, antiagainst, arpith-jacob, mgester, lucyrfox, liufengdb, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D73295