[HLSL] Add support for the HLSL matrix type (#159446)
fixes #109839
This change is really simple. It creates a matrix alias that will let
HLSL use the existing clang `matrix_type` infra.
The only additional change was to add explict alias for the typed
dimensions of 1-4 inclusive matricies available in HLSL.
Testing therefore is limited to exercising the alias, sema errors, and
basic codegen.
future work will add things like constructors and accessors.
The main difference in this attempt is the type printer and less of an
emphasis on tests where things overlap with existing `matrix_type`
testing like cast behavior.
