Apple Inc.’s iPhone staged a rebound in China last month with shipments rising 52% amid a flurry of discounts from retail partners.The latest figures from the China Academy of Information and Communications Technology showed smartphone shipments surging in the country, of which roughly 3.5 million units came from foreign brands, according to a Bloomberg calculation. The iPhone accounts for the vast majority of such devices, and its bounceback comes after it registered growth in March following s...