Thirty years after killing his sister’s boyfriend in a sensational Chicago crime that launched an international search, Andrew Suh walked out of prison in western Illinois Friday thanks to a new state law that grants retroactive sentencing credit for rehabilitative programs he had completed. Suh, who turned 50 earlier this month, was greeted by a half dozen supporters and his lawyer, Candace Chambliss, legal director of the Illinois Prison Project, about 9:45 a.m. outside the gates of Kewanee Life-Skills Re-Entry Center. Among his awaiting supporters was Sungmin Kim, an attorney and member of …