Fix https://issues.apache.org/bugzilla/show_bug.cgi?id=54513
Multiple bugs in the new Poller implementation (r1433976) when
the endpoint is stopped and then started
 - Ensure old Poller thread stops
 - Ensure old AsyncTimeout thread stops
 - Ensure old sendfile thread stops
 - Ensure sockets in keep-alive are closed

git-svn-id: https://svn.apache.org/repos/asf/tomcat/trunk@1441807 13f79535-47bb-0310-9956-ffa450edef68