By Jonathan Stempel NEW YORK (Reuters) – Roger Ng, the former Goldman Sachs banker convicted for helping loot Malaysia’s 1MDB sovereign wealth fund, on Friday sued the government’s star witness Tim Leissner for more than $130 million, alleging fraud. In a complaint filed in a New York state court in Manhattan, Ng accused his former boss of repeatedly lying in order to steal his investments in energy drink maker Celsius Holdings and artificial intelligence company Sentient Technologies. The complaint said Leissner, a former Goldman partner, stole Ng’s money to cover his own defense costs in a r…