Constraints information for coefficients that are not the ansatz function

In the case of operator splitting the form might depend on additional coefficients, that are not the ansatz function. Those coefficients usually come from solving other problems and might have constraints. For the driver block generation we need to know the type of the underlying GFS which needs to know about the constraints.

So far we have no way of tying that information to the coefficient in the UFL file (or the ini file). This means that driver block generation for operator splitting is not yet fully functional. Besides this issue it should work (search in the code for this issue to find the places where the constraints information is needed.