Makes emitting shaders from fx.c easier, and brings parsing failures
upfront.
Non-effect target profiles don't perform any type checks on
ConstructGSWithSO(), nor use shader objects in any way, but they do
check if the argument count is correct.
So we create a GeometryShader object with NULL decl and profile when
targeting non-effect profiles, so our type checks still work and
implicit conversions aren't attempted.
b17923b5ba