Avoid a memory leak with the background processing thread

git-svn-id: https://svn.apache.org/repos/asf/tomcat/trunk@1471024 13f79535-47bb-0310-9956-ffa450edef68
Fix https://issues.apache.org/bugzilla/show_bug.cgi?id=54800
Fix memory leaks when using WebSocket client triggered by JVM created threads not having the correct context class loader set.

git-svn-id: https://svn.apache.org/repos/asf/tomcat/trunk@1471029 13f79535-47bb-0310-9956-ffa450edef68
Fix https://issues.apache.org/bugzilla/show_bug.cgi?id=54792
Application shouldn't be trying to close the session in an @onClose method.

git-svn-id: https://svn.apache.org/repos/asf/tomcat/trunk@1471031 13f79535-47bb-0310-9956-ffa450edef68