No longer save/load water region invalidation states

Move InitializeWaterRegions to AllocateMap
No longer ForceUpdate in InitializeWaterRegions

src/genworld.cpp

@@ -34,7 +34,6 @@
 #include "string_func.h"
 #include "thread.h"
 #include "tgp.h"
-#include "pathfinder/water_regions.h"
 #include "signal_func.h"
 #include "newgrf_industrytiles.h"
 #include "station_func.h"
@@ -192,8 +191,6 @@ static void _GenerateWorld()
 			}
 		}
 
-		InitializeWaterRegions();
-
 		BasePersistentStorageArray::SwitchMode(PSM_LEAVE_GAMELOOP);
 
 		ResetObjectToPlace();