Liza Minnelli, 62, is one of two performers ever to engineer the major-awards sweep – Tony, Oscar, Emmy, Grammy. (Quick: name the other without Googling.) Miss Liza is getting ready for two weeks at the Palace Theater on Broadway. Here is a shot from rehearsal. It used to be said that, after a nukular holocaust, the only life left on planet earth would be cockroaches and Cher. I think we should amend that to: cockroaches, Cher, and Liza.