Open this photo in gallery: An Alibaba Group office building in Beijing, on Aug. 9, 2021.TINGSHU WANG/Reuters Investors wiped out some $20-billion off Alibaba Group’s BABA-N market value on Friday after it scrapped plans to spin off its cloud business, citing uncertainties over U.S. curbs on exports to China of chips used in artificial intelligence applications. Alibaba Group’s Hong Kong shares closed down 10 per cent, their biggest single-day drop in more than a year. It was the first market reaction in Asia since the stunning strategy reversal was announced late on Thursday, after which the company’s U.S. listed securities…