Starbucks is losing its prime spot among chains racing to meet China’s growing thirst for coffee. Luckin Coffee has surpassed Starbucks as China’s biggest coffee chain by sales and units, company reports show, a comeback for the Chinese company after an accounting scandal that stalled its growth. Flush with capital and under new leadership, Luckin now operates about 13,300 stores, with all but a handful located in China. That is roughly double Starbucks’s 6,800 locations in the country. To fuel its growth, Luckin has tapped rapid delivery services, mobile payment options and offerings such as a cheese-flavored latte that has…