Fix https://issues.apache.org/bugzilla/show_bug.cgi?id=45428
Trigger a thread dump to aid diagnostics if Tomcat fails to stop in a timely manner.

git-svn-id: https://svn.apache.org/repos/asf/tomcat/tc7.0.x/trunk@1511436 13f79535-47bb-0310-9956-ffa450edef68