Stabilize pg_dump output order for similarly-named triggers and policies.

The code only compared two triggers' names and namespaces (the latter
being the owning table's schema).  This could result in falling back
to an OID-based sort of similarly-named triggers on different tables.
We prefer to avoid that, so add a comparison of the table names too.
(The sort order is thus table namespace, trigger name, table name,
which is a bit odd, but it doesn't seem worth contorting the code
to work around that.)

Likewise for policy objects, in 9.5 and up.

Complaint and fix by Benjie Gillam.  Back-patch to all supported
branches.

Discussion: https://postgr.es/m/CAMThMzEEt2mvBbPgCaZ1Ap1N-moGn=Edxmadddjq89WG4NpPtQ@mail.gmail.com

src/bin/pg_dump/pg_dump_sort.c

@@ -164,6 +164,7 @@ DOTypeNameCompare(const void *p1, const void *p2)
 		FuncInfo   *fobj2 = *(FuncInfo *const *) p2;
 		int			i;
 
+		/* Sort by number of arguments, then argument type names */
 		cmpval = fobj1->nargs - fobj2->nargs;
 		if (cmpval != 0)
 			return cmpval;
@@ -202,10 +203,33 @@ DOTypeNameCompare(const void *p1, const void *p2)
 		AttrDefInfo *adobj1 = *(AttrDefInfo *const *) p1;
 		AttrDefInfo *adobj2 = *(AttrDefInfo *const *) p2;
 
+		/* Sort by attribute number */
 		cmpval = (adobj1->adnum - adobj2->adnum);
 		if (cmpval != 0)
 			return cmpval;
 	}
+	else if (obj1->objType == DO_POLICY)
+	{
+		PolicyInfo *pobj1 = *(PolicyInfo *const *) p1;
+		PolicyInfo *pobj2 = *(PolicyInfo *const *) p2;
+
+		/* Sort by table name (table namespace was considered already) */
+		cmpval = strcmp(pobj1->poltable->dobj.name,
+						pobj2->poltable->dobj.name);
+		if (cmpval != 0)
+			return cmpval;
+	}
+	else if (obj1->objType == DO_TRIGGER)
+	{
+		TriggerInfo *tobj1 = *(TriggerInfo *const *) p1;
+		TriggerInfo *tobj2 = *(TriggerInfo *const *) p2;
+
+		/* Sort by table name (table namespace was considered already) */
+		cmpval = strcmp(tobj1->tgtable->dobj.name,
+						tobj2->tgtable->dobj.name);
+		if (cmpval != 0)
+			return cmpval;
+	}
 
 	/* Usually shouldn't get here, but if we do, sort by OID */
 	return oidcmp(obj1->catId.oid, obj2->catId.oid);