Ramin Setoodeh Executive EditorSharon Stone wasn’t getting the bids that she wanted.Around midnight on Friday night in France, after a dazzling fashion show on the lawn of a mansion in Antibes, the actor-turned-emcee was auctioning off 32 one-of-a-kind gowns by designers such as Versace, Louis Vuitton, Dior, Givenchy and Balenciaga at the amfAR Cannes gala.Joined onstage by the 32 models who’d walked a makeshift runway — which was so slippery, two of them had tripped — Stone was ready to pocket