When historians look back to the summer of 2020, they might feel like time travelers in the Hollywood movie “Back to the Future.” “Empire Strikes Back” was the number one film during the second week of July. The Star Wars movie was first released 40 years ago. A week earlier, “Ghostbusters” which had come out in 1984 was the top movie. A week later, it was the 1993 film “Jurassic Park.” The coronavirus pandemic seems to bring back a lot of things from the past, from puzzles to drive-in theaters. But old movies are back for a different reason. Most of the big movie theaters are still closed. So major new movie releases have been postponed to late August or early September.