Revert "Bulk-reads and Request caching in Course Grade Report"

common/djangoapps/course_modes/models.py

common/djangoapps/course_modes/tests/test_models.py

common/djangoapps/request_cache/__init__.py

common/djangoapps/request_cache/middleware.py

common/djangoapps/student/models.py

common/djangoapps/student/roles.py

lms/djangoapps/certificates/models.py

lms/djangoapps/certificates/tests/tests.py

lms/djangoapps/grades/models.py

lms/djangoapps/grades/new/course_grade_factory.py

lms/djangoapps/grades/tests/test_new.py

lms/djangoapps/grades/tests/test_tasks.py

lms/djangoapps/instructor_task/tasks_helper/grades.py

lms/djangoapps/instructor_task/tests/test_tasks_helper.py

lms/djangoapps/verify_student/models.py

openedx/core/djangoapps/course_groups/cohorts.py

openedx/core/djangoapps/credit/models.py

openedx/core/djangoapps/credit/tests/test_api.py

openedx/core/djangoapps/user_api/course_tag/api.py

openedx/core/djangoapps/user_api/partition_schemes.py