Sharply split on whether the law-of-the-case doctrine barred Illinois Tool Works from invoking the Workers’ Compensation Act’s exclusive-remedy provision as an affirmative defense on remand from a 2014 decision that concluded a DuPage County judge erred in spontaneously applying the exclusive-remedy law as an additional basis for granting ITW’s request for summary judgment — in a lawsuit where Michael Hiatt, an employee of Western Plastics Inc. in west suburban Addison, alleged his arms were …