Fix: depot-related commands did not validate depot tiles properly (#9948)

The bug comes in two slices:

1) the functions never actually checked if "tile" was a depot tile.
   This allowed executing the function on tile 0, where are the
   things like shadows of aircrafts are.
2) BuildDepotVehicleList() first checked if a vehicle is in a depot
   before checking if it was a primary vehicle. This is invalid
   for aircraft.

Fixing the first hides the second, and fixing the second makes the
first non-exploitable. But, fixing both felt like the best thing
to do.

src/vehicle_cmd.cpp

@@ -634,6 +634,7 @@ CommandCost CmdMassStartStopVehicle(DoCommandFlag flags, TileIndex tile, bool do
 	if (vehicle_list_window) {
 		if (!GenerateVehicleSortList(&list, vli)) return CMD_ERROR;
 	} else {
+		if (!IsDepotTile(tile) || !IsTileOwner(tile, _current_company)) return CMD_ERROR;
 		/* Get the list of vehicles in the depot */
 		BuildDepotVehicleList(vli.vtype, tile, &list, nullptr);
 	}
@@ -666,6 +667,7 @@ CommandCost CmdDepotSellAllVehicles(DoCommandFlag flags, TileIndex tile, Vehicle
 	CommandCost cost(EXPENSES_NEW_VEHICLES);
 
 	if (!IsCompanyBuildableVehicleType(vehicle_type)) return CMD_ERROR;
+	if (!IsDepotTile(tile) || !IsTileOwner(tile, _current_company)) return CMD_ERROR;
 
 	/* Get the list of vehicles in the depot */
 	BuildDepotVehicleList(vehicle_type, tile, &list, &list);

src/vehiclelist.cpp

@@ -80,21 +80,21 @@ void BuildDepotVehicleList(VehicleType type, TileIndex tile, VehicleList *engine
 			case VEH_TRAIN: {
 				const Train *t = Train::From(v);
 				if (t->IsArticulatedPart() || t->IsRearDualheaded()) continue;
-				if (t->track != TRACK_BIT_DEPOT) continue;
+				if (!t->IsInDepot()) continue;
 				if (wagons != nullptr && t->First()->IsFreeWagon()) {
 					if (individual_wagons || t->IsFreeWagon()) wagons->push_back(t);
 					continue;
 				}
+				if (!t->IsPrimaryVehicle()) continue;
 				break;
 			}
 
 			default:
+				if (!v->IsPrimaryVehicle()) continue;
 				if (!v->IsInDepot()) continue;
 				break;
 		}
 
-		if (!v->IsPrimaryVehicle()) continue;
-
 		engines->push_back(v);
 	}