Alibaba Group Holding Ltd.’s interest in purchasing Yahoo Inc. of the U.S. provides the latest test of whether Chinese companies with global ambitions can expand while staying in line with Beijing’s economic and social controls. Alibaba Chief Executive Jack Ma told a gathering in the U.S. on Friday that the Chinese e-commerce company was interested in buying the U.S. Internet search company and had been approached by private-equity firms and others about a potential deal. It is unclear whether Alibaba has taken formal steps to make an offer, and a spokesman declined to offer further details.