diff: LST - remove deprecated logic

myPreviousBaseRevision is always null, as resetForBaseRevisionLoad() is not used anymore
diff: LST - remove useless statement

myPartner will be cleared by myPartner.clear()
diff: LST - cleanup
diff: LST - cleanup
diff: LST - cleanup
diff: LST - cleanup
diff: LST - cleanup
diff: LST - we don't need to update base revision, if it's already up-to-date
diff: LST - @NotNull
diff: cleanup
diff: LST - cleanup
diff: LST - cleanup
diff: LST - cleanup
diff: LST - cleanup
diff: merge two related functions
diff: LST - reuse LST instead of creation/deletion every time

this will fix IDEA-129533, as the issue was in non-refreshing of LST on reportTrackerBaseLoadFailed()
diff: LST - clarify debug messages
diff: LST - inline function

This is needed for optimisation, as VirtualFile.getPath() could be slow.
diff: LST - cleanup
diff: LST - simplify