“Even small leakages effectively become a transfer of public funds beyond Malaysia’s borders,” says an economist.    JOHOR BAHRU: Just 200m from the Woodlands Causeway, the mood at a Shell station in Johor Bahru is taut. Pump attendants linger, watchful as Singapore-registered cars pull in. Their eyes follow every move of the drivers, as they lift the nozzle to their tanks before clicking back into place.  The concern is not just what goes into vehicles, but what might leave in portable