It would be nice to see Jason Statham try something more demanding than his standard, tough-guy role. Still, he has so thoroughly perfected the part that it’s easy to enjoy his performances. In “Parker,” Statham goes back to the well, playing the title character: a professional thief with an interesting code of ethics. In an early scene, Parker says he won’t steal from people who can’t afford it, won’t hurt people who don’t deserve it and always follows through on a promise.