Specifically, this transforms:
builtin "generic_add"<Builtin.Vec4xInt32>(
->
builtin "add_Vec4xInt32"(
If we do not have a static overload for the type, we just leave the generic call
alone. If the generic builtin takes addresses as its arguments (i.e. 2x
in_guaranteed + 1x out), we load the arguments, evaluate the static overloaded
builtin and then store the result into the out parameter.