By Stephen Culp NEW YORK (Reuters) – U.S. stocks ended the session lower and benchmark Treasury yields continued their ascent on Thursday after investors weighed generally upbeat earnings against the prospect that the Federal Reserve could hold firm on its aggressive policy for longer than they had hoped. All three major U.S. stock indexes reversed an earlier rally, turning red after remarks from Philadelphia Federal Reserve President Patrick Harker suggested the central bank will “keep raising rates for a while.” Harker’s comments also helped support the 10-year Treasury yield’s climb past 14…