By Pete Schroeder WASHINGTON (Reuters) -U.S. stocks surged Tuesday on the back of stronger than expected corporate earnings, but bleak forecasts on global economic growth pushed up bond yields and drove down oil. The tech-heavy Nasdaq led the way for gains in U.S. markets, as many corporations began to report stronger than expected earnings. Those reports helped investors shake off warnings from global forecasters of a slowdown in economic growth, which weighed on other sectors like bonds and oil. Of the 49 companies in the S&P 500 that have reported quarterly earnings as of Tuesday, nearly 80…