Generate annotations on enum entry constants in bytecode

 #KT-5665 Fixed
Minor, remove dependency of everything on "descriptor.loader.java"

Everything already depends on "frontend.java" which exports
"descriptor.loader.java"
Support object declarations in DI generator
Test generator: inline the constant FQ name
Test generator: improve import statements in generated tests

- delete unused "junit.framework.Assert" import
- delete import of the abstract super class, because it always happens to be in
  the same package
- reorder other imports in such way that "Optimize Imports" action in IDEA will
  mostly have no effect in generated tests. However this will still happen in
  tests without any nested test cases (useless imports of InnerClasses etc.)
Regenerate tests after recent generator improvements
Minor, fix warnings and inspections in JetTestUtils
Minor, update obsolete message in JetTestUtils