There's a new Wall Street TACO index - and this one is saying it's time for Trump to strike a deal

By Steve GoldsteinIs it TACO time at the White House?JPMorgan has devised a TACO barometer, referring to the expression Trump Always Chickens Out, as a way to predict the behavior of the mercurial world leader.JPMorgan isn't the first to do so - Signum Global Advisers has its own version. The Signu…