By ERIC SCHMITT and JULIAN E. BARNES The United States abruptly withdrew all 12 B-1 Air Force bombers from an air base in southern England based on new information that commanders received about a potential drone attack ordered by Iran’s Revolutionary Guard, according to U.S. and British officials. The suspected attack was part of a complex, multipronged Iranian plot to strike aircraft and kill some of the several hundred American personnel stationed at the base, RAF Fairford, the officials…