Fix https://issues.apache.org/bugzilla/show_bug.cgi?id=57047
Fix possible false test failure when the session gets closed before the message write can complete.


git-svn-id: https://svn.apache.org/repos/asf/tomcat/tc7.0.x/trunk@1634150 13f79535-47bb-0310-9956-ffa450edef68