findClass(String, GlobalSearchScope) is invoked for example when we're
resolving supertypes of classes in Java libraries. Previously, it never
found nested classes and falled back to CoreJavaFileManager's
implementation, which lacks a fix for the original issue (KT-12664,
which was fixed in JvmDependenciesIndex in ff783f1f and 2c344635)
#KT-16931 Fixed
Original commit: c67eb84369
Dmitry Gridin