[mlir] Flip Vector dialect accessors used to prefixed form.

[mlir] Flip Vector dialect accessors used to prefixed form.

This has been on _Both for a couple of weeks. Flip usages in core with
intention to flip flag to _Prefixed in follow up. Needed to add a couple
of helper methods in AffineOps and Linalg to facilitate a pure flag flip
in follow up as some of these classes are used in templates and so
sensitive to Vector dialect changes.

Differential Revision: https://reviews.llvm.org/D122151