Use bulk_operations in group access tests.

lms/djangoapps/courseware/tests/test_group_access.py

@@ -126,6 +126,7 @@ class GroupAccessTestCase(ModuleStoreTestCase):
         self.course = CourseFactory.create(
             user_partitions=[self.animal_partition, self.color_partition],
         )
+        with self.store.bulk_operations(self.course.id, emit_signals=False):
             chapter = ItemFactory.create(category='chapter', parent=self.course)
             section = ItemFactory.create(category='sequential', parent=chapter)
             vertical = ItemFactory.create(category='vertical', parent=section)