By JIANG JUNZHE and MATT OTT, Associated Press Markets on Wall Street and in Europe declined rapidly early Friday morning after President Donald Trump posted a pair of tariff threats on social media, one aimed at Apple and the other at the European Union. Futures for the S&P 500 and the Dow Jones Industrial Average slid 1.5% and Nasdaq futures tumbled 1.7% before the bell. Oil prices fell and Treasury yields sank as well. Markets took a sharp tu…