Joan Cutler has an impossible decision to make in “Eternity.” The newly deceased character, played by Elizabeth Olsen, has one week to decide who she wants to spend her afterlife with and two husbands lurking and hoping that she’ll choose them. Luke ( Callum Turner ) is the dashing one who died in the Korean War right as they were starting a life together. Larry ( Miles Teller ) is the other one, kind of common, kind of a crank, but the person who she was married to for 65 years.