SHANGHAI/BEIJING (Reuters) – Chinese e-commerce giant Alibaba Group Holding Ltd is expected to post its weakest quarterly revenue growth on record, Thomson Reuters data shows, a slowdown analysts say will heat up the battle with smaller rival JD.com Inc in a tougher economy. Alibaba’s revenue for the quarter ending December is projected to grow at 26.6 percent, according to a Thomson Reuters SmartEstimate survey of 28 analysts, which would be the slowest rate since the company started publishing such data 3-1/2 years ago.