Two of the holiday season’s biggest releases, “Dune: Part 3” and “Avengers: Doomsday,” are on a collision course of “Barbenheimer”-like proportions on Dec. 18, but IMAX CEO Rich Gelfond believes “Dune” already has the advantage. The third installment of Denis Villeneuve’s series has already secured IMAX and 70mm IMAX screens for opening weekend, leaving Marvel’s
