Harold Pinter’s “The Birthday Party,” one of his so-called comedies of menace, is often associated with a feeling particular to a time and place: the fear of postwar Europeans who, still reeling from bombings and the Gestapo, knew that terror can strike capriciously, raining down at random, leaving no one, ever, completely safe. Yet nothing feels period about ACT’s production of the 1957 play, which opened Wednesday, Jan.