Comparison leads to removal of entries on creation of SuperSets

The comparator defined in org.fortiss.af3.exploration.util.DSMLModelElementFactory.createSuperSet(...) in the frame of #4126 (closed) does not distinguish between objects ...

• which have the same ID (except in the case where the ID is 0).
• whose ID is 0 and whose names are equal.

As the entries are stored in a set, objects deemed equal are discarded as duplicates.