A group of people, ranging in age, gather at a drive-in theater outside of Dallas on a Friday evening. Their intentions vary; some are there for the entertainment of a low-budget 1970s film, others seek romance or conflict, and still others plan to commit robbery. “Drive-In” (1976) feels like “American Graffiti,” but relocated to an average drive-in somewhere in the United States, and with a more exaggerated sense…