Post-rebase fix cachegroup API tests for localizationMethods
Post-rebase fix cachegroup API tests for localizationMethods

Use the new CacheGroupNullable methods.

hbeatty/incubator-trafficcontrol,hbeatty/incubator-trafficcontrol,hbeatty/incubator-trafficcontrol,hbeatty/incubator-trafficcontrol,hbeatty/incubator-trafficcontrol,hbeatty/incubator-trafficcontrol,hbeatty/incubator-trafficcontrol,hbeatty/incubator-trafficcontrol,hbeatty/incubator-trafficcontrol,hbeatty/incubator-trafficcontrol