Merge r1753594 from trunk:

* Prevent redirect loops between workers within a balancer by limiting the
  number of redirects to the number balancer members.

PR: 59864

Submitted by: rpluem
Reviewed by: rpluem, jim, ylavic


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/branches/2.4.x@1756563 13f79535-47bb-0310-9956-ffa450edef68