Paula McFadden knows: In romance, actors all follow the same stage instruction: Exit. Without warning, her actor boyfriend split today for a movie role and sublet their Manhattan apartment. The new tenant's name: Elliot Garfield. Profession: actor. Richard Dreyfuss and Marsha Mason deliver comedy, zingy repartee and bitter-to-best romance in The Goodbye Girl, a lustrous charmer featuring Dreyfuss' Academy Award-winning Best Actor performance.