In anticipation of the need for is_patch_constant_func in
sm4_generate_vsir_reg_from_deref(), in order to generate vsir
registers from InputPatch/OutputPatch dereferences.
If the parameter is HLSL_STORAGE_IN, we add a cast from the arg to the
param type so that it can enter the function, however this cast should
not be considered part of the lhs on the implicit assignment that happens
if the var is also HLSL_STORAGE_OUT.
While so far it has been posible to do this at parse time, this must
happen after knowing if the complex cast is on the lhs or not.
The modified tests show that before this patch we are currently
miscompiling when this happens, because a complex lhs cast is transformed
into a load, and add_assigment() just stores to the generated "cast"
temp.
For example, given two arguments, half3 and float, and two functions,
func(float, float) and func(float3, float3), fxc/d3dcompiler prefers to
widen both arguments to float3.
Commit 1ed8d907b3 inadvertently dropped
emitting the tessellator domain for domain shaders. Although Vulkan
environments allow us to write the tessellator domain from the hull
shader, the domain shader, or both, that's not generally true for OpenGL
environments.
