LOS ANGELES — A multimillion dollar collection of Andy Warhol portraits of Muhammad Ali and other sports superstars was stolen from a Los Angeles home, police said Friday. The 11 color screenprints, each 40 inches square, were taken from businessman Richard Weisman's home sometime between Sept. 2 and 3, said Detective Mark Sommer of the Los Angeles Police Department's art theft detail. Ten of the portraits featured famous athletes of the 1970s. The other was of Weisman. Some of the