NEW YORK — It’s as bad as the Giants initially feared: Sterling Shepard tore the ACL in his left knee. His season is over, if not his Giants career. The veteran wide receiver dropped to the MetLife Stadium turf in agony and grabbed his left leg after suffering a non-contact injury late in Monday night’s fourth quarter against the Dallas Cowboys. It’s fair to wonder if Shepard should have been on the field at all. He made a fast return from last December’s torn left Achilles. That was also a non-contact injury sustained on the MetLife Stadium turf, on Dec. 19 against the Philadelphia Eagles. Sh…