Call checker and declaration checker are used in order to preserve backward compatibility.
Attempt to use classifier usage checker was not good enouth,
since not all errors found with it would actually be reported before.
For example types and constructor calls don't cause supertypes to resolve,
so missing supertypes would not lead to errors in case they are the only use of class name.
Updated tests failing due to missing Java dependencies in superclasses.
Pavel Kirpichenkov