Add support to test large redis connection quota

Change-Id: If17f432fb2c461aaf86fdc4e4fce8dd164fa4537
Reviewed-on: http://reviews.cloudfoundry.org/13027
Tested-by: CI Master <cf-ci@rbcon.com>
Reviewed-by: Tang Rui <rtang@vmware.com>
Reviewed-by: Michael Zhang <zhangcheng@rbcon.com>