A day laborer from Annandale has been charged with murder in the stabbing death of a Fairfax County contractor who had hired him to work in a Chevy Chase home, police said yesterday.The slaying occurred after the day laborer stole stereo equipment and jewelry from the house where they were working, court records say. The issue of day laborers gathering informally to be hired by contractors has been contentious recently, particularly in Herndon, where the town government is trying to accommodate workers with a gathering place away from a 7-Eleven on Herndon's main street. Police said yesterday that other...