There is introduced algorithm of resolution with jumps: before
resolution of some class we resolve all status of members of its
supertypes, so we can properly determine inherited visibility
and modifiers
In particular, this commit includes:
* Attempt to abstract access to FirSourceElement via FirModifier
* Add more visit functions to DeclarationCheckersDiagnosticComponent
* Add messages+factories for 4 modifier-related errors and warnings
* Introduce FirModifierChecker
Jinseong Jeon