TOKYO (Reuters) - U.S. stock futures erased losses and Asian stocks held flat on Monday, trying to shake off worries that rising coronavirus cases in the United States could scupper a quick economic rebound from the massive downturn triggered by the pandemic.U.S. S&P 500 futures rose 0.4%, having erased early losses of 1.05% while Japan's Nikkei also eked out gains of 0.1%, similarly recovering from early losses.MSCI's broadest index of Asia-Pacific shares outside Japan was almost flat while..