LINCOLN, Neb. — U.S. Supreme Court Chief Justice John G. Roberts Jr. expressed concern Friday about growing partisanship in the judicial confirmation process and a public perception that politics factor into the court’s rulings. Roberts told an audience at the University of Nebraska-Lincoln College of Law that the partisan atmosphere in Washington, D.C., would make it unlikely for justices such as Antonin G. Scalia, widely viewed as a conservative, or Ruth Bader Ginsburg, who is seen as liberal, to win …