Analysis   China’s largest internet corporations are decimating their walled-off ecosystems amid Beijing tightening regulations on its tech giants. The latest instance came when Alibaba Group allowed rival Tencent’s payment system to be integrated with some of its apps this week.  Such practices have come under scrutiny from Chinese regulators, which have launched new rules across areas from data security to anti-monopoly. Alongside an existing payment service Alipay run by its affiliate Ant Group, Alibaba now allows users to purchase items on some of its apps via WeChat Pay, the payment service run by its rival Tencent. Alibaba confirmed the change with state-run media The Paper on Sept. 28, adding that “the company will continue to find common ground with peers to serve consumers better.” Alibaba reportedly added some online services to accept WeChat Pay, including its food delivery app Ele.me, video service Youku, online ticketing platform Damai, e-book reader …