IDEA-66101 Mercurial: "hg merge" support missing

*Extract the code from HgIntegrateEnvironment to a separate Mercurial | Merge action.
*Return null in HgVcs#getIntegrateEnvironment() to hide the action for Mercurial.
*Add annotation for HgPlatformFacade argument in HgVcs.
*Add warning notification in HgCommandResultNotifier
javafx: instantiate with valueOf fixed
javafx: variables resolve (IDEA-100318)
javafx: valueOf method search extracted
javafx: do not uppercase constants (IDEA-100397)
Hg refactor LightTest structure.

 *Use static import for Executor and HgExecutor methods call.
Subversion: SvnRenamedTest - correctly verify output to do not fail on Mac
Merge remote branch 'origin/master'
IDEA-60552 (todo node renderer fixed)
Deprecated SyntaxHighlighterColors replaced with JavaHighlightingColors for Java