Cook County Circuit Judge Jessica A. O’Brien was on the other side of the bench today as a prosecutor and a defense attorney gave opening statements in her trial on charges that she took part in a $1.4 million scheme to defraud lenders.But the 12 jurors and two alternates serving in the case in U.S. District Judge Thomas M. Durkin’s courtroom were not told O’Brien has served as a judge since 2012.Instead, Assistant U.S. Attorney Matthew F. Madden and Ricardo Meza of Greensfelder Hemker & Gale P.C …