Compilers of some java-based languages (like Scala) produce classes with names different from those declared in sources.
If for some language qualified names of compiled classes differ from names declared in the sources, a NameMapper must be registered
within the DebuggerManager class.
Multiple registered mappers forms a "chain of responsibility" and the first non-null result is returned.
If no mappers are registered or all mappers returned null, the result of
PsiClass.getQualifiedName() will be used as a qualified name of the compiled class