SONAR-7168 fix HardStopWatcher support for external restart

when SQ instance is restarted by another process (eg. orchestrator) which does not clean the temp directory before restarting, the HardStopWatcher of the newly started SQ will detect the stop flag targeted at the previous SQ and immediatly shutdown the App JVM but let the two child JVM process up
to avoid this, the HardStopWatcher is now created only after the temp directory has been reset by the App process