[2.3.x] + implement improvement #1655
https://java.net/jira/browse/GRIZZLY-1655

"RoundRobinConnectionDistributor can be optimized to not use AtomicInteger"
[2.3.x] + fix issue #1654
https://java.net/jira/browse/GRIZZLY-1654

"HttpServletRequest.changeSessionId doesn't register new session id"