NewGRF: Elide unmasked vehicle callbacks where possible

This includes:
* CBID_VEHICLE_32DAY_CALLBACK
* CBID_VEHICLE_REFIT_COST
* CBID_VEHICLE_MODIFY_PROPERTY
  This is on a per-property basis

The main benefit of this is to avoid callbacks not handled by the
vehicle's current sprite group from using the full graphics chain as
the "default" branch in the callback switch.
In the case where the graphics chain is long/expensive, a lot of work
had to be done before a callback failure result was eventually returned.

src/saveload/afterload.cpp

@@ -938,6 +938,8 @@ bool AfterLoadGame()
 		_settings_game.vehicle.train_braking_model = TBM_ORIGINAL;
 	}
 
+	AfterLoadEngines();
+
 	/* Update all vehicles */
 	AfterLoadVehicles(true);
 
@@ -4012,6 +4014,7 @@ void ReloadNewGRFData()
 	RecomputePrices();
 	/* reload vehicles */
 	ResetVehicleHash();
+	AfterLoadEngines();
 	AfterLoadVehicles(false);
 	StartupEngines();
 	GroupStatistics::UpdateAfterLoad();