[Matrix] Add option to use row-major matrix layout as default.

This patch adds a -matrix-default-layout option which can be used to
set the default matrix layout to row-major or column-major (default).

The initial patch updates codegen for loads, stores, binary operators
and matrix multiply.

Reviewers: anemet, Gerolf, andrew.w.kaylor, LuoYuanke

Reviewed By: anemet

Differential Revision: https://reviews.llvm.org/D76325