Fix generating multifile facade with all members private (in bytecode)
leading to delegate not being generated for corresponding light class
#KT-20966 Fixed
Allow to get annotation list and to invoke `findAnnotation` without building delegate
Introduce KtLightNullabilityAnnotation which holds nullability information and is built
before delegate is built
To provide consistency between light classes and their delegates
IdeLightClass#testExtendingInterfaceWithDefaultImpls still failing since
we do not generate implementations delegating to DefaultImpls of superinterfaces