Australian officials defended their suspension of the fruitless deep-sea sonar search for Malaysia Airlines Flight 370, insisting on Wednesday that the enormous costs involved played no role in their decision to halt the nearly three-year hunt. Australia’s Transport Minister Darren Chester also said that while the search had been called off on Tuesday, work behind the scenes would go on, with experts continuing to analyze data associated with the doomed aircraft’s final hours and examining any future debris that washes ashore.