The ServerSetupObserver contains several collections for tracking various states. A clean up needs to be done as there is a good chance some of these collections could leak as seen in WFARQ-16.

There is also the issue described in https://issues.jboss.org/browse/WFLY-5229 where the ServerSetupTask.tearDown() may fail manual mode tests if the server was already shutdown. The error will not be descriptive. It may just be better to log an error. We should least throw a better exception.