fix: CCW combine turns

#731

Author: Peter Vaiko

scripts/ai/turns/AITurn.lua

@@ -490,7 +490,7 @@ function CombineHeadlandTurn:turn(dt)
         maxSpeed = self:getReverseSpeed()
         moveForwards = false
         gx, gz = self:getGoalPointForTurn(moveForwards, nil)
-        if dx < 0.2 then
+        if math.abs(dx) < 0.2 then
             self.state = self.states.REVERSE_ARC
             self:debug('Combine headland turn start reversing arc')
         end