Something’s missing in the UK publicity poster for “The Heat,” the new crazy-cop flick starring Melissa McCarthy and Sandra Bullock. What is it? Oh, about 30 pounds, according to a mounting chorus of critics. The new buddy-cop comedy, which opens in the U.S. June 28 and across the pond July 31, has McCarthy playing (what else?) the big ol’ crazy, sloppy Hardy to Bullock’s svelte and Spanx-wearing Laurel. Still, even though it’s the premise, the poster makers seemed determined to slim McCarthy down.