You’re buried in a snow cave with no light and a depleting supply of oxygen. But then you hear scratching on the surface, get a whiff of cold air and the tawny muzzle of a golden retriever thrusts through the crust toward you. If you’re an avalanche victim, the dog has just saved your life. All three of the South Shore ski resorts have specialized avalanche rescue dog teams comprised mostly of golden retrievers and labs ready for a situation like this — a solo skier or rider gets caught without a transceiver in a slide and needs to be …