Core/Vehicles: Add an assert to trace down crash in Vehicle::RelocatePassengers

src/server/game/Entities/Vehicle/Vehicle.cpp

@@ -432,6 +432,8 @@ void Vehicle::RelocatePassengers(float x, float y, float z, float ang)
     for (SeatMap::const_iterator itr = m_Seats.begin(); itr != m_Seats.end(); ++itr)
         if (Unit *passenger = itr->second.passenger)
         {
+            ASSERT(passenger->IsInWorld());
+
             float px = x + passenger->m_movementInfo.t_pos.m_positionX;
             float py = y + passenger->m_movementInfo.t_pos.m_positionY;
             float pz = z + passenger->m_movementInfo.t_pos.m_positionZ;