Observed a hard to reproduce test failure with the non-blocking IO tests. Can't reproduce it yet. Working assumption is that Poller and application thread have a different view of the async field on the SocketWrapper so make all the flags the Poller uses volatile.

git-svn-id: https://svn.apache.org/repos/asf/tomcat/trunk@1551731 13f79535-47bb-0310-9956-ffa450edef68