Fix several cases of wrongly using broken runways.

The usual symptom here was the game breaking when a carrier is
destroyed. The carrier would no longer be operational but missions would
be assigned there that could not generate flight plans.

game/procurement.py

@@ -258,11 +258,9 @@ class ProcurementAi:
     ) -> Iterator[ControlPoint]:
         distance_cache = ObjectiveDistanceCache.get_closest_airfields(request.near)
         threatened = []
-        for cp in distance_cache.airfields_within(request.range):
+        for cp in distance_cache.operational_airfields_within(request.range):
             if not cp.is_friendly(self.is_player):
                 continue
-            if not cp.runway_is_operational():
-                continue
             if cp.unclaimed_parking(self.game) < request.number:
                 continue
             if self.threat_zones.threatened(cp.position):

game/theater/controlpoint.py

@@ -517,7 +517,7 @@ class ControlPoint(MissionTarget, ABC):
         max_retreat_distance = nautical_miles(200)
         # Skip the first airbase because that's the airbase we're retreating
         # from.
-        airfields = list(closest.airfields_within(max_retreat_distance))[1:]
+        airfields = list(closest.operational_airfields_within(max_retreat_distance))[1:]
         for airbase in airfields:
             if not airbase.can_operate(airframe):
                 continue

game/threatzones.py

@@ -124,7 +124,7 @@ class ThreatZones:
         cls, location: ControlPoint, max_distance: Distance
     ) -> Optional[ControlPoint]:
         airfields = ObjectiveDistanceCache.get_closest_airfields(location)
-        for airfield in airfields.airfields_within(max_distance):
+        for airfield in airfields.all_airfields_within(max_distance):
             if airfield.captured != location.captured:
                 return airfield
         return None