Robert Redford and Sydney Pollack are in the Dominican Republic to film "Havana," a romantic thriller set in Cuba in the late 1950s. The movie, which also stars Alan Arkin, has a monster $50-million budget, which is 1/12th of the Dominican Republic's gross national product. . . . Woody Allen is busy with a new movie but, as usual, he's not telling anyone about the plot or title. There are reports, however, that the cast includes William Hurt, Judith Ivey, Joe Mantegna, Alex Baldwin, Blythe Danner, model Elle McPherson and, of course, Allen's personal love interest, Mia Farrow. . . .