WFLY-1506 Cleanup the PooledEJBLifecycleTestCase 

https://issues.jboss.org/browse/WFLY-1506

The commit here cleans up the PooledEJBLifecycleTestCase to prevent the intermittent failures we have been noticing in this testcase. In theory, we wouldn't really need this testcase at all since most of the functionality that is being tested in here is already indirectly being tested in some other testcases. But I decided to let the cleaned up version stay since there isn't other tests which directly test the functionality being tested here. Furthermore, the test doesn't really do anything heavy duty to warrant a delete due to the intermittent issues and this test indeed ended up (unintentionally) exposing an issue in our messaging subsystem which I'm going to file a separate JIRA for.