“Hairspray,” Adam Shankman’s buoyant adaptation of the Broadway musical inspired by the 1988 John Waters comedy, is currently running 94 percent favorable reviews at Rotten Tomatoes (the contrarian is David Edelstein of New York Magazine, who long ago worked for The Post). I’m giving it four stars today in The Post. It’s one of the best cast films in years — from top-billed John Travolta, Michelle Pfeiffer and Christopher Walken to the movie’s real star, dazzling plus-size newcomer Nikki Blonsky, pictured here with “High School Musical” heartthrob Zac Efron.