Fix: Crash when attempting to load old save game with GRFs set

GroupStatistics pool was not initialised before trying to delete vehicles (specifically, trams with no tram track)

src/saveload/afterload.cpp

@@ -1893,6 +1893,7 @@ bool AfterLoadGame()
 	}
 
 	if (IsSavegameVersionBefore(SLV_62)) {
+		GroupStatistics::UpdateAfterLoad(); // Ensure statistics pool is initialised before trying to delete vehicles
 		/* Remove all trams from savegames without tram support.
 		 * There would be trams without tram track under causing crashes sooner or later. */
 		RoadVehicle *v;