Long control: add a_change cost in e2e mode (#26237)

Add e2e cost
old-commit-hash: dcde942d9f

selfdrive/controls/lib/longitudinal_mpc_lib/long_mpc.py

@@ -253,7 +253,8 @@ class LongitudinalMpc:
       cost_weights = [X_EGO_OBSTACLE_COST, X_EGO_COST, V_EGO_COST, A_EGO_COST, a_change_cost, J_EGO_COST]
       constraint_cost_weights = [LIMIT_COST, LIMIT_COST, LIMIT_COST, DANGER_ZONE_COST]
     elif self.mode == 'blended':
-      cost_weights = [0., 0.1, 0.2, 5.0, 0.0, 1.0]
+      a_change_cost = 40.0 if prev_accel_constraint else 0
+      cost_weights = [0., 0.1, 0.2, 5.0, a_change_cost, 1.0]
       constraint_cost_weights = [LIMIT_COST, LIMIT_COST, LIMIT_COST, 50.0]
     else:
       raise NotImplementedError(f'Planner mode {self.mode} not recognized in planner cost set')