Stocks Drop After Greenspan Testimony NEW YORK - Investors adopted a wait-and-see attitude on the economy, despite Federal Reserve Chairman Alan Greenspan's improved assessment, and bid stocks modestly lower Wednesday as Wall Street waits for better economic and earnings news.    While Greenspan said the economy has "regained some traction" after the summer's slowdown, investors looked past his congressional testimony, focusing instead on uncertainty about the health of the economy, third-quarter earnings pre-announcements and fiscal policy...