RE: Per-table resync for logical replication subscriptions

Dear Cagri,

Thanks for the patch. I have comments for v7.

```
+ /*
+ * The relation set is now known to be fed by this subscription alone, and
+ * this subscription has no running workers, so nothing that replicates
+ * into these relations is still holding them. Take the level the
+ * truncate needs.
+ */
+ foreach_oid(relid, relids)
+ LockRelationOid(relid, AccessExclusiveLock);
```

Here we does not acquire a lock for the root table if the publication publishes
only leaves. So subscriptions can be created after
CheckRefreshTableNotInOtherSubscriptions(). I considered a race condition due to
this with LLM: See attached patch.

Also, I found the test could fail like:

```
[14:44:37.892](0.014s) not ok 35 - only the named inheritance parent is reset
[14:44:37.893](0.000s) # Failed test 'only the named inheritance parent is reset'
# at /home/hayato/postgres/src/test/subscription/t/039_refresh_table.pl line 407.
[14:44:37.893](0.000s) # got: 'tab_inh_c=s,tab_inh_p=i'
# expected: 'tab_inh_c=r,tab_inh_p=i'
```

It tried to ensure the tab_inh_c was synchronized, right? Should accept 's'

Best regards,
Hayato Kuroda
FUJITSU LIMITED