HAMPSHIRE, UK — Global shipments of smartphones reached 338 million units in the second quarter of 2015, but growth in the smartphone market slowed to 16% year-over-year, according to UK-based mobile analyst firm Juniper Research.According to a press release issued Thursday by Juniper Research, the launch of Huawei’s P8 smartphone helped the Chinese manufacturer to surge ahead of its midrange rivals with more than 30 million smartphone shipments in Q2 2015, representing nearly 50% year-over-year growth. Huawei’s nearest Chinese rival, Xiaomi, shipped 20.5 million smartphone units in the second quarter, representing an increase of one-third compared to this time last...