Japan’s economy shrank an annualized real 1.8 percent in the January-March quarter, revised up from its earlier reading of a 2.0 percent decline, the Cabinet Office said Monday. It was the first contraction in two quarters due to soft domestic demand and the effects of a safety data-rigging scandal at a Toyota Motor Corp. group firm that dented production and exports. Adjusted for inflation, Japan’s gross domestic product fell 0.5 percent from the previous quarter, unchanged from the preliminary report.