By Jeff Mason WASHINGTON (Reuters) – President Joe Biden expressed confidence on Friday that momentum would shift back in favor of Democrats for the November midterm elections, despite polls favoring Republicans in races that will determine which party controls the U.S. Congress. Fresh from a trip to Pennsylvania on Thursday to boost John Fetterman, the state’s lieutenant governor and Democratic candidate for the U.S. Senate, Biden said legislative wins and economic trends would push Democrats towards a win. “The polls have been all over the place,” Biden told reporters at the White House afte…