It's been more than three decades, but retired Cook County Associate Judge Sam L. Amirante still remembers the night John Wayne Gacy came to his office and gulped down two coffee cups full of whiskey.That's because what followed Gacy's quickly downed cocktails was a confession that made Amirante's jaw drop and eventually resulted in one of Cook County's most notorious criminal trials."It was the longest night of my life," Amirante said of that late night in 1978 when Gacy told him he killed 34 young men and …