Before this commit, we added Enum.entries only in case when
LanguageFeature.EnumEntries was ON (with an exception in K1/Java case).
In this commit we add Enum.entries unconditionally, and in case
the language feature is OFF we filter them out during tower resolve.
Because those test are single Java files, many of them use a top-level
class as a container for multiple classes to be tested. Such tests do
almost nothing if those nested classes aren't handled.
Really, this commit implements early J2K mapping for all Java types.
It's questionable and probably wrong at least for super-types,
because, for example, we cannot resolve spliterator() in classes
derived from java.lang.Iterable
Mikhail Glukhikh