Update fork of Apache Commons Pool2 to latest trunk to pick up fixes including one for a potential infinite loop.

git-svn-id: https://svn.apache.org/repos/asf/tomcat/tc8.0.x/trunk@1643815 13f79535-47bb-0310-9956-ffa450edef68
Merged revision 1643937 from tomcat/trunk:
Additional method was introduced to StandardRoot in order to be able to extend classResources.

git-svn-id: https://svn.apache.org/repos/asf/tomcat/tc8.0.x/trunk@1643938 13f79535-47bb-0310-9956-ffa450edef68