For the instructions which execute after the IdPass check we can provide
the Instruction instead of the spv_parsed_instruction_t. This
Instruction class provides a bit more context (like the source line)
that is not available from spv_parsed_instruction_t.
This CL moves the validation code to the val:: namespace. This makes it
clearer which instance of the Instruction and other classes are being
referred too.
- Test validation success for OpEmitVertex OpEndPrimitive
- Test missing capabilities for primitive instructions
- Primitive instructions require Geometry execution model
