RE: 024_add_drop_pub.pl might fail due to deadlock

Dear Ajin,

Thanks for patches! While checking, I recalled that the backpatch policy [1].
We must not modify definitions of opened functions but this does. Can you define
another function like UpdateSubscriptionRelStateEx or something on the back
branches?

Another comment:
```
@@ -328,9 +328,13 @@ UpdateSubscriptionRelState(Oid subid, Oid relid, char state,
Datum values[Natts_pg_subscription_rel];
bool replaces[Natts_pg_subscription_rel];

- LockSharedObject(SubscriptionRelationId, subid, 0, AccessShareLock);
-
- rel = table_open(SubscriptionRelRelationId, RowExclusiveLock);
+ if (already_locked)
+ rel = table_open(SubscriptionRelRelationId, NoLock);
```

Can we assert that RowExclusiveLock for pg_subscription_rel has already been
acquired, by using CheckRelationOidLockedByMe() family?

Also, I'm now bit confusing for which branches are really affected. Can you
create all patches for branches, attach at the same e-mail and add some summary
what you want to fix?
E.g., you provided a patch for HEAD/PG15/PG14, what about PG18, 17, 16 and 13?
If not needed, why?

[1]: https://www.postgresql.org/docs/devel/xfunc-c.html#XFUNC-API-ABI-STABILITY-GUIDANCE

Best regards,
Hayato Kuroda
FUJITSU LIMITED