Support spirv glsl ext op with scalar args for distance, length, & reflect

[raoanag]

As per discussion on Refract PR, SPIRV supports operands with both scalar and vector types.

Need to update error handling and removing any vector type block for SPIRV and add relevant tests to check the implementation.

[damyanp]

@farzonl / @spall: Do we need to update or add additional functional tests as we do this?

[farzonl]

Technically we aren’t doing anything wrong. But it is different codegen from DXC. I think this is low priority.

[farzonl]

I also don’t think the scalar cases of these opcodes are producing any hardware optimized results and we probably will have more behavior conformant implementation leaving this as is.