South Korean stocks quickly fell from grace following the U.S. and Israeli strikes on Iran. But Wall Street doesn't see that as a harbinger for anything that's to come in the U.S. The benchmark Kospi Index tumbled more than 12% Wednesday — its worst-ever single day of trading. Korean stocks have plungedmore than 18% so far this week, on track for their biggest weekly loss since 2008. South Korea's stock market was dark on Monday for a national holiday. But a sharp selloff came Tuesday when