In a very old tradition, the Pittsburgh Public Theater has chosen to follow the season's highpoint, a wonderful "Hamlet," with that tragedy's complete antithesis, the Reduced Shakespeare Company's "William Shakespeare's Long Lost First Play (abridged)." Whereas "Hamlet" is . . . well, let's assume you know what "Hamlet" is . . . this "Long Lost Shakes" is puns and pratfalls, sly comedy and chaos.