Merge pull request #11445 from edx/ormsbee/clear_cache_in_tests

common/djangoapps/util/tests/test_django_utils.py

common/lib/xmodule/xmodule/modulestore/tests/django_utils.py

lms/djangoapps/course_structure_api/v0/tests.py

lms/djangoapps/courseware/tests/test_views.py

lms/djangoapps/instructor_task/tests/test_tasks_helper.py

openedx/core/djangoapps/bookmarks/tests/test_views.py

openedx/core/djangoapps/content/course_overviews/tests.py