Rename `go_to_next_user_class` to be more meaningful
Rename `go_to_next_user_class` to be more meaningful

New name is `try_next_user_class_to_stay_balanced_during_ramp_up` which indicates what this function accomplishes.

mbeacom/locust,mbeacom/locust,locustio/locust,mbeacom/locust,mbeacom/locust,locustio/locust,locustio/locust,locustio/locust