A superior court judge has handed Wynn Resorts a key legal victory, ruling a group of taxpayers didn’t have legal standing to challenge the state’s sale of land to the casino company. Judge Janet L. Sanders’s 12-page order, which was dated last week, dismissed a lawsuit brought by 40 taxpayers – including prominent anti-casino activist John Ribeiro – and MBTA riders, who argued that the T’s decision to sell three Everett parcels of land to Wynn for $6 million violated state bidding laws.