NEW YORK — Wall Street has turned the clock back to 1997. Investors unable to extinguish their worries about a recession that has no end in sight dumped stocks again Monday. The Dow Jones industrial average tumbled 251 points to its lowest close since Oct. 28, 1997, while the Standard & Poor's 500 index logged its lowest finish since April 11, 1997. All the major indexes slid more than 3 percent.