US STOCKS-Wall St flat as U.S.-China trade deal optimism fades

U.S. stocks halted a three-day winning streak on Monday, as oil prices dived 2% and rising doubts over how quickly a partial U.S.-China trade deal announced on Friday could be sealed.Energy majors such as Exxon Mobil Corp and Chevron Corp were the biggest drags on the S&P 500 index, as oil prices gave up last week's gains following caution around the trade deal.The S&P 500 and Dow Jones indexes had ended Friday with their first weekly gain in a month after Washington signaled the two sid