Citing findings that Chicago police routinely use excessive force in violation of the Fourth Amendment, a federal judge declined to throw out a claim that the city is liable for the death of a robbery suspect who was killed when a police pursuit ended in a crash.In a written opinion last week, U.S. District Judge Thomas M. Durkin did not rule on the merits of allegations that officer Dean W. Ewing used too much force in the incident and that the city has a practice of tolerating and covering up such wrongdoing.But Durkin …