Uncertainty surrounding China's stimulus plans is causing volatility for Tencent.Tencent (TCEHY -9.54%) stock is sinking in Tuesday's trading. The Chinese technology and media giant's share price was down 8.4% as of 2:45 p.m. ET, according to data from S&P Global Market Intelligence.Chinese stocks are losing ground today following indications that additional economic stimulus from the country's government won't be forthcoming in the near future. Tencent and many other China-based companies saw their valuati ...