Because PackageViewDescriptor may consist of several package fragments from
different modules (see LazyPackageViewDescriptorImpl#fragments), we now filter
out fragments from irrelevant modules before rendering them into the .txt
Consider FQN 'a.b.c'.
If 'a' is a classifier in the current scope,
resolve rest in the corresponding class scope.
Otherwise (if 'a' is a package),
find the maximum possible prefix 'a.b' resolving to a package,
resolve rest in the corresponding package scope.
Alexander Udalov