ST6RI-896 getDirectedUsage broken on an ActionDefinition or Constraint Definition

[seidewitz]

This PR fixes a bug which caused the method Definition::getDirectedUsage to always return the empty list for ActionDefinitions and ConstraintDefinitions even if they did, in fact, have directedFeatures that were Usages.

Cause

The method getDirectedUsage was implemented by a DefaultDerivedPropertySettingDelegate, returning a DerivedEObjectEList subsetting directedFeature for elements that are Usages. However, the property directedFeature is redefined as parameter for Behaviors, and ActionDefinition and ConstraintDefinition are kinds of Behavior. Because of this, the dynamic get for directedFeature in DerivedEObjectEList was not returning anything, because directedFeature was no longer a feature of the EClass.

Fix

Added an explicit Definition_directedUsage_SettingDelegate that extends DefaultPropertySettingDelegate and overrides the method basicGet to check if the owner is an instance of ActionDefinition or ConstraintDefinition. If so, then a DerivedEObjectEList is returned that derives from parameter instead of directedFeature. Otherwise, DefaultDerivedPropertySettingDelegate::basicGet is used.