Worries of a deepening China economic slowdown intensified on Friday after a private survey showed the factory sector shrank at its fastest rate in almost 6-1/2-years in August, hammering global stocks and commodity prices. The gloomy figure sent investors fleeing for cover in gold and bonds, fearing China’s sagging economy would translate into slower global growth and muddy the outlook for the timing of the first U.S. interest rate hike in nearly a decade.