FORSYTH COUNTY — Political newcomer Michael Williams defeated longtime incumbent state Sen. Jack Murphy in a bruising Republican primary runoff election Tuesday that signals a shift in Forsyth County politics. Murphy, who was seeking a fifth term in the District 27 post he has held since 2006, is the senior member of local state legislative delegation. Williams garnered 10,796 votes, or about 66 percent of the total, in Tuesday’s runoff to Murphy’s 5,518 votes, or about 34 percent of the vote.