Wall Street got a reality check as a bruising sell-off in several technology giants fuelled concern the artificial intelligence frenzy that has powered the equity bull market might be overblown.The tech rout engulfed global stocks as worries about frothy valuations ignited a fresh bout of volatility after a nearly three-month surge in riskier assets.The S&P fell 1.4 per cent. The benchmark index is coming off 11 weekly gains out of the last 12, led largely by technology stocks.The Dow Jones...