Before the coronavirus sent stock markets tumbling at the fastest pace since the 2008 financial crisis, Dymon Asia Capital (Singapore) sensed trouble.The hedge fund firm was combining information on past outbreaks with a raft of so-called alternative data, including Google searches in the US and daily readings from China on everything from road congestion to flight schedules and test-kit availability. The numbers convinced Dymon to take short positions against the S&P 500 and an index of…