Another attempt to fix random fails of test `test_compound_key_dictfield`.
Another attempt to fix random fails of test `test_compound_key_dictfield`.

MakerReduxCorp/mongoengine,cogniteev/mongoengine,MongoEngine/mongoengine,MakerReduxCorp/mongoengine,cogniteev/mongoengine,Davidrjx/mongoengine,ProgressivePlanning/mongoengine,ConsumerPhysics/mongoengine,Davidrjx/mongoengine