Donald Clark Jr. always wanted to be a trial lawyer. Perhaps he was inspired by some of the characters portrayed in the classic movies he saw on television: Gregory Peck as Atticus Finch, Spencer Tracy as Clarence Darrow or even Paul Newman as the washed-up alcoholic in “The Verdict.”Or maybe he was encouraged by those great TV series — “Perry Mason” and “The Defenders.”No matter, that is precisely what this 63-year-old graduate of Williams College and Rutgers Law School became …