[git] prefer long CLI parameter name
[git] IDEA-124254 cherry-picked highlighter: don't remove highlighting if cancelled

That means that one more task was fired. Removing highlighting if
cancelled will lead to the same effect as in IDEA-124254.

Other cases when the task is cancelled are not interesting, because
they remove highlighting manually.
[vcs-log] minor: remove some duplications
[vcs-log] move util methods to the VcsLogUtil class from VcsLogFileFilter; move VcsLogFileFilter to the appropriate place and make it package private; use ContainerUtil.new<SomeCollection> methods IDEA-75093
[vcs-log] DeepCompareAction takes visible roots into account IDEA-75093