Envy, about best friends (Ben Stiller and Jack Black) torn apart when one becomes rich, is like one of those cliffhanger rides at an amusement park: It starts out nice and smooth, then the bottom drops out. The movie’s release date was repeatedly delayed, and it seems to have seen the light of day not because any problems have been solved but because everyone involved has given up. By its end, Stiller and Black might as well be waving a white flag.