[git] cleanup, null annotations
[git] reduce logging noise

This is actually a valid situation to request GitRepositoryManager#getRepositoryForFile for non-Git files. Can be used, for instance, in #update() of Git-only actions to check if the action should be visible at all (when it is under Svn, for instance).
More cases in message box test action
Noise reduction
IDEA-99470 literal constructors can have named args
IDEA-99527 @Immutable forces field to be final
EA-42128 - NPE: GrMapType.getInternalCanonicalText
IDEA-99690 Groovy: introduce variable should remember if I use explicit type
javafx: add single imports for unresolved tags
javafx: move around