NEW YORK/SAN FRANCISCO (Reuters) - Investors could be forgiven for doing a double-take: Wait, we're back in a bull market? The Dow Jones Industrial Average's surge of over 20% from its coronavirus-induced recent low this week, by one definition used on Wall Street, suggests a new bull market. The surge came on hopes a $2 trillion (1.64 trillion pounds) stimulus measure would flood the country with cash in a bid to counter the economic impact of the intensifying pandemic.But that definition..