The Boston Celtics are tearing apart teams at home like the days when Larry Bird, Kevin McHale and Robert Parish roamed the fabled parquet. Kevin Garnett scored 23 points and the Celtics improved to 10-0 at home with a 112-84 win over the Toronto Raptors on Friday night. Paul Pierce had 18 points and Ray Allen 13 for Boston (16-2), which is off to the NBA’s best start and its best home mark since…