[SM6.10] Add HLSL MatrixRef type and lower CreateMatrix intrinsic

[V-FEXrt]

• Adds the __builtin_LinAlg_MatrixRef type to HLSL
• implements the first stage of __builtin_LinAlg_CreateMatrix which currently returns an unannotated MatrixRef.
• updates HLSL intrinsics to operate over __builtin_LinAlg_MatrixRef
• Adds the appropriate tests

Notes:

• Annotation is intentionally ignored in this change and will be managed seperately
• The PR couldn't be split further because __builtin_LinAlg_CreateMatrix was needed for any effective test of __builtin_LinAlg_MatrixRef

[hekota]

LGTM!

[hekota]

Suggested change

	// AST: |-CXXRecordDecl {{[^ ]+}} <<invalid sloc>> <invalid sloc> implicit referenced class __builtin_LinAlg_MatrixRef definition
	// AST-NEXT: | |-FinalAttr {{[^ ]+}} <<invalid sloc>> Implicit final
	// AST-NEXT: | |-AvailabilityAttr {{[^ ]+}} <<invalid sloc>> Implicit 6.10 0 0 ""
	// AST-NEXT: | |-HLSLMatrixRefAttr {{[^ ]+}} <<invalid sloc>> Implicit
	// AST-NEXT: | |-FieldDecl {{[^ ]+}} <<invalid sloc>> <invalid sloc> implicit h 'int'
	// AST: CXXRecordDecl {{.*}} implicit referenced class __builtin_LinAlg_MatrixRef definition
	// AST-NEXT: FinalAttr {{.*}} Implicit final
	// AST-NEXT: AvailabilityAttr {{.*}} Implicit 6.10 0 0 ""
	// AST-NEXT: HLSLMatrixRefAttr {{.*}} Implicit
	// AST-NEXT: FieldDecl {{.*}} implicit h 'int'

Just a nit - consider simplifying the checks for better readability.

[spall]

looks okay to me but I'm not confident enough in this area to approve