Well, who knew? One of the few shows that John Kander and Fred Ebb (the songwriting team behind such hits as Cabaret and Chicago) never managed to land on Broadway turns out to be their missing masterpiece. A musical version of Frederich Durrenmatt's famous play about a town offered a devil's bargain by the world's richest woman was given a lovely, vest-pocket revival by the Signature Theatre in Arlington, Va. The pessimistic view of human nature and allegorical, theater-of-the-absurd touches bring out the curdled dark side of Kander and Ebb's Broadway pizzazz. And Chita Rivera, as the sinister plutocrat, shows that the old trouper can still strut her stuff — even on one leg. So why isn't this show on Broadway?