Deadlock when starting and immediately stopping a gateway

#### Can the bug be reproduced in a Kaazing demo out-of-the-box?
Yes

#### Steps to reproduce the problem
In a test, instantiate a Gateway, start it and immediately stop it.

#### Expected behavior
The gateway is stopped.

#### Actual behavior
Sometimes, the server becomes stuck. This is a sporadic behavior

This issue is the cause of many other sporadic issues in tests.