NEWYORK(Reuters)-TheS&P500dippedinalatedeclineonFridayasWal-MartdroppedfollowingareportofaweakstarttoFebruarysales,thoughtheindexjustbarelyextendeditsstreakofweeklygainstoseven.Equitieswerelittlechangedformuchofthesession,withinvestorsfindingfewreasonstomakebigbetsfollowinganextendedrallyonWallStreet,butstocksturnedlowerinafternoonaction.Wal-MartStoresIncdropped2.1percent...