don't ruin cached_context_grants_right? in test mode

Change-Id: I543cd76eac17dfc60b3ce058f735450f4c54c863
Reviewed-on: https://gerrit.instructure.com/32054
Reviewed-by: Cody Cutrer <cody@instructure.com>
Tested-by: Jenkins <jenkins@instructure.com>
Product-Review: Cody Cutrer <cody@instructure.com>
QA-Review: Cody Cutrer <cody@instructure.com>