Donald Trump said in an interview that economic conditions are so perilous that the country is headed for a “very massive recession” and that “it’s a terrible time right now” to invest in the stock market, embracing a distinctly gloomy view of the economy that counters mainstream economic forecasts. The New York billionaire dismissed concern that his comments — which are exceedingly unusual, if not unprecedented, for a major party front-runner — could potentially affect financial markets. “I know the Wall Street people probably better than anybody knows them,” said Trump, who has misfired on such predictions in the past....