A disgruntled worker stalked a colleague down a Midtown street, shot him dead and then turned his weapon on random pedestrians outside the Empire State Building — killing at least one innocent bystander and shooting up to seven others before he was cut down by a cop on foot patrol, sources told The Post. -snip- The gunman followed his victim down 33rd Street before opening fire outside Legend’s Bar. the sources said. With his target dead, he then headed over to the Empire State Building and did the unthinkable — unleashing a fusillade of shots in the heart of the...