Feat: Support testing of node sharing between constraints

Assume two constraints sharing the same UniConstraintStream:

    @Override
    public Constraint[] defineConstraints(ConstraintFactory factory) {
        UniConstraintStream<VehicleShift> nonVirtualVehicles = factory.forEach(VehicleShift.class)
                .filter(vehicleShift -> !vehicleShift.isVirtual());

        return new Constraint[] {
                // hard
                endLocationMaxArrivalTimeHardLimit(nonVirtualVehicles),
                lastVisitMaxDepartureTimeHardLimit(nonVirtualVehicles)
        };
    }

These constraints cannot be unit-tested using the ConstraintVerifier as the constraintVerifier.verifyThat() expects a method reference with a single parameter, the ConstraintFactory .