Pcm2Java reactions: Empty constructor not removed after OperationRequiredRole removed from Component

[h4uges]

An OperationRequiredRole is mapped to a constructor containing an assignment. If an OperationRequiredRole is removed from a component (e.g. moved to another component) and no other Pcm model elements are mapped to parts of the constructor, a empty constructor remains. We expect Pcm2Java reactions to remove constructors that contain no statements.

#243 adds a unit test which shows that behaviour (OperationRequiredRoleMappingTransformationTest.testChangeOperationRequiredRole). Currently the empty constructor is asserted by the unit test