“And down the stretch they come!” It’s a phrase that calls to mind galloping hooves and crumpled vouchers. But is it enough to sustain a copyright? Arguing just that, longtime Triple Crown race announcer Dave Johnson brought a federal complaint for damages Wednesday against the makers of the 2014 film “St. Vincent.” Starring as the titular Vincent, Bill Murray utters the famous phrase over an hour into the running time as his character races down a hospital hallway in wheelchairs with his child sidekick, Oliver, played by Jaeden Liebene.