Fixed problems handling passive connections in Remoting #2878

- Fixed potential race in EndpointWrite when TakeOff is processed
- Reenabled accidentally disabled gremlin due to changed defaults
- Fixed EndpointRegistry incorrectly handling passive connections
Merge pull request #1028 from drewhk/wip-2878-out-of-order-msg-in-stresstest-drewhk

Fixed problems handling passive connections in Remoting #2878