NEW YORK — Benedict Cumberbatch is ready to bring a little magic to “Saturday Night Live.” The “Doctor Strange in the Multiverse of Madness” actor will host “SNL” on May 7, the day after his much-anticipated Marvel movie arrives in theaters. Cumberbatch will be joined on the episode by musical guest Arcade Fire, NBC announced Sunday. It’s the second “SNL” hosting gig for Cumberbatch, who previously starred on an episode of the sketch comedy series in 2016. “Doctor Strange in the Multiverse of Madness” stars Cumberbatch as the titular superhero sorcerer whose manipulation of time caused big pro…