Nobody would win. Jugsy may be invulnerable and durable, but Hulk attains a comparable status relatively early on in the battle. And since Hulk's boundless determination keeps him coming and coming until Juggy is dead(without knowing that Cain just won't die), Cain is likely to get bored with the fight long before Hulk does. He'll have no other choice but to walk/run away. If he doesn't he'll just get smacked around until the end of time.