ATLANTA — Rep. Jack Kingston of Savannah and former Dollar General CEO David Perdue advanced to a GOP runoff after Tuesday's primary, setting up a battle between a veteran congressman and an opponent billing himself as an outsider in a race that will help determine which party controls Congress. Perdue, who had been leading in the polls, and Kingston, who dominated in fundraising, secured their spots with the help of a major TV advertising blitz in the final few weeks and left the state's sizeable tea party crowd without a favored candidate. In unofficial returns, Perdue had 31 percent of the vote to Kingston's 26 percent with 90 percent of precincts reporting.