[Matrix] Generalize ColumnMatrixTy to MatrixTy (NFC).

This patch sets the stage for supporting both row and column major
layouts for matrixes. It renames ColumnMatrixTy to MatrixTy, adds
booleans indicating the underlying layout to both MatrixTy and ShapeInfo
and generalizes the methods of MatrixTy to support both row and column
major layouts.

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

Reviewed By: anemet

Differential Revision: https://reviews.llvm.org/D76324