[clang] [Matrix][Clang][HLSL] Move MaxMatrixDimension to a LangOpt (PR #163307)

[Chris B via cfe-commits]

https://github.com/llvm-beanz approved this pull request.

This looks reasonable to me. I've suggested a few extra test cases to consider. It looks like the C++ matrix dimensions are reasonably well covered over in https://github.com/llvm/llvm-project/blob/main/clang/test/SemaCXX/matrix-type.cpp.

https://github.com/llvm/llvm-project/pull/163307