A top adviser for Caesar Barber's lawsuit against four national restaurants, alleging that they made him obese, has publicly dismissed the suit and announced that overweight children will be the new focus of a revised suit.   John Banzhaf, George Washington University Law Professor and point man on the Barber case, commented during a debate this week on CNN's Crossfire: "That [Barber] suit is gone" and it "no longer applies". He said a new lawsuit is currently being constructed, which alleges that children were lured into restaurants with playgrounds and kids meals and are now overweight as a result.