McDonald’s is rolling out a retro run of its shape-shifting “Changeables” Happy Meal toys starting Tuesday, aiming to cash in on nostalgia nearly four decades after the line first debuted. The fast-food giant is reviving the Transformers-like toys that turn familiar McDonald’s items into robots or dinosaurs — a fan-favorite throwback that originally launched in 1987 and later returned in 1989 and 1990.