Gautam Adani’s flagship firm called off its $2.5 billion share sale in a dramatic reversal on Wednesday as a rout sparked by a U.S. short-seller’s criticisms wiped billions more off the value of the Indian tycoon’s stocks. The withdrawal of the Adani Enterprises share offering marks a stunning setback for Adani, the school dropout-turned-billionaire whose fortunes rose rapidly in recent years in line with stock values of his businesses.