ISLAMABAD, Pakistan — A Chinese worker on a dam project in northern Pakistan has been arrested and imprisoned on accusations of blasphemy, in a rare case of a foreigner being swept up in Pakistan’s harsh and controversial blasphemy laws. The Chinese man was identified in a Pakistani police report as “Mr. Tian” and described as a transportation supervisor at the Dasu hydropower project, led by China’s Gezhouba Group construction and engineering company. The police report, which was obtained by The New York Times, said the man was on a field…