[git] Fix already disposed

Save the reference in advance to avoid getService from a bg thread.
[git] Don't spam to stdout in tests unless test failed
[tests] extract dumping log to stdout to the common test framework
[git tests] Make sure other tear downs finish even if one fails
[git tests] fix GitAddSteps

* explicitly mark file as dirty
* use synchronous CLM.ensureUpToDate.
[git tests] turn cuke tests back on.
[vcs] Fix already disposed exception

It was thrown from UpdatingChangeListBuilder.isExcluded because
checkIsDisposed just checked the updater's stopped-status,
but not the disposal state.
[git tests] Remove the test root directory after test execution, reorder teardowns
[git tests] Fix testdata for cherry-pick

-x adds a newline between the subject and appended message
[git tests] simpler method names
[git tests] fix paths comparison