Remove unnecessary list_free() calls in OpenTableList().

OpenTableList() is invoked at most once per DDL statement, from
CreatePublication() and AlterPublicationTables(), and everything it
builds (relids, relids_with_rf, and relids_with_collist) is allocated
in the command's own memory context. That context is reclaimed as
soon as the command finishes, so explicitly freeing relids and
relids_with_rf here served no purpose.

Reported-by: Peter Smith <smithpb2250@gmail.com>
Suggested-by: Tom Lane <tgl@sss.pgh.pa.us>
Author: Peter Smith <smithpb2250@gmail.com>
Reviewed-by: shveta malik <shveta.malik@gmail.com>
Reviewed-by: shihao zhong <zhong950419@gmail.com>
Reviewed-by: surya poondla <suryapoondla4@gmail.com>
Discussion: https://postgr.es/m/CAHut+Pt3bgyt==d6GCj=p9qu4sVSH_KQWLN7cMaH0RdJCO-K_Q@mail.gmail.com

src/backend/commands/publicationcmds.c

@@ -1977,9 +1977,6 @@ OpenTableList(List *tables)
 		}
 	}
 
-	list_free(relids);
-	list_free(relids_with_rf);
-
 	return rels;
 }