For anyone who is exhausted by the male antihero, “American Gigolo,” on Showtime, is good news. Our main man, Julian Kaye (Jon Bernthal), has not committed one selfish act in his sad life. He has been groomed, pimped, framed—you name it—and still he looks out on the site of his trials, the putrid vista of present-day Los Angeles, with moist eyes, conveying resignation.