fix negative tile cost from pathfinding skill

lib/CPathfinder.cpp

@@ -1227,7 +1227,7 @@ int CPathfinderHelper::getMovementCost(
 	/// TODO: by the original game rules hero shouldn't be affected by terrain penalty while flying.
 	/// Also flying movement only has penalty when player moving over blocked tiles.
 	/// So if you only have base flying with 40% penalty you can still ignore terrain penalty while having zero flying penalty.
-	int ret = hero->getTileCost(*dt, *ct, ti);
+	ui32 ret = hero->getTileCost(*dt, *ct, ti);
 	/// Unfortunately this can't be implemented yet as server don't know when player flying and when he's not.
 	/// Difference in cost calculation on client and server is much worse than incorrect cost.
 	/// So this one is waiting till server going to use pathfinder rules for path validation.

lib/mapObjects/CGHeroInstance.cpp

@@ -70,7 +70,7 @@ static int lowestSpeed(const CGHeroInstance * chi)
 
 ui32 CGHeroInstance::getTileCost(const TerrainTile & dest, const TerrainTile & from, const TurnInfo * ti) const
 {
-	unsigned ret = GameConstants::BASE_MOVEMENT_COST;
+	int64_t ret = GameConstants::BASE_MOVEMENT_COST;
 
 	//if there is road both on dest and src tiles - use road movement cost
 	if(dest.roadType != ERoadType::NO_ROAD && from.roadType != ERoadType::NO_ROAD)
@@ -105,7 +105,7 @@ ui32 CGHeroInstance::getTileCost(const TerrainTile & dest, const TerrainTile & f
 		if(ret < GameConstants::BASE_MOVEMENT_COST)
 			ret = GameConstants::BASE_MOVEMENT_COST;
 	}
-	return ret;
+	return (ui32)ret;
 }
 
 ETerrainType::EETerrainType CGHeroInstance::getNativeTerrain() const