'findKotlinClassOrContent()' does not really distinguish between
outer class names and package path components, so it might return
'foo/bar/Baz.Boo' for 'foo/bar/Baz/Boo'. Possibly because
'findKotlinClassOrContent()' potentially returns a raw byte array,
ClassId checking is supposed to be performed in
'extractClassMetadata()'. For Java, it happens inside
'FirJavaFacade.findClass()', yet for Kotlin the check was absent.