By Luc Cohen NEW YORK (Reuters) -A former Goldman Sachs banker should be convicted of helping loot billions of dollars from Malaysia’s 1MDB sovereign wealth fund and causing “immeasurable” harm, a U.S. prosecutor told jurors in her closing argument on Monday. But a lawyer for the defendant Roger Ng, Goldman’s former top investment banker for Malaysia, countered that Ng had been falsely implicated in the looting by his former boss Tim Leissner, the government’s star witness. Ng, 49, has pleaded not guilty to conspiring to launder money and violating an anti-corruption law. Prosecutors said he h…