Japan’s economy sank deeper into its worst post-war contraction in the second quarter as the coronavirus jolted businesses more than initially thought, underscoring the daunting task the new prime minister faces in averting a steeper recession.Other data put that challenge in perspective, with household spending and wages falling in July as the broadening impact of the pandemic kept consumption frail even after lockdown measures were lifted in May.The world’s third-largest economy shrank an…