NEW YORK — The federal government knows who killed Jam Master Jay — and the killer’s not one of the two men on trial for the Run-DMC icon’s murder, the suspects’ defense attorneys said Wednesday. In their closing arguments, the lawyers for Karl Jordan Jr. and Ronald “Tinard” Washington blamed the DJ’s 2002 murder on another man, Jay Bryant — who confessed to his uncle about the killing, and whose DNA was on a hat found at the murder scene. “Who is Jay Bryant? Well, Jay Bryant is literally reasonable doubt in this case,” Jordan’s lawyer, Michael Hueston, told the jury. “We have a single person …