Addiction left David Dastmalchian living out of a car, but after getting clean and working on a Batman movie, ‘Ant-Man and the Wasp’ and ‘Prisoners,’ he is in a different place entirely. David Dastmalchian is trying to keep it together. He’s wearing a police uniform, but he doesn’t quite know why. He’s supposed to act like he’s been shot, but he doesn’t quite know why. What the young actor does know: He’s just been ushered onto the streets of Chicago, where Christopher Nolan is staging one of the most ambitious scenes in his secretive Batman sequel The Dark Knight.