"Give Peace a Chance" is apparently no longer the tune surrounding Central Park's Strawberry Fields, after a stroller mishap led to a man getting slashed. Yesterday evening, a man accidentally bumped into a stroller being pushed by a man and a woman near the park at 72nd St. and Central Park West. Foregoing the usual, "Excuse me," and "Good evening" of the average spring constitutional, the stroller bumper and the child's pushers got into a......