Performance optimization: updated the worker MPM to recycle

per-transaction pools instead of destroying them.  Based on
Ian's benchmark testing, this reduces CPU utilization by
about 1% on Solaris.


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@93386 13f79535-47bb-0310-9956-ffa450edef68