Remove duplicate code in planner.c.

I noticed while hacking on join UNION transforms that planner.c's
function get_base_rel_indexes() just duplicates the functionality of
get_relids_in_jointree().  It doesn't even have the excuse of being
older code :-(.  Drop it and use the latter function instead.

src/backend/optimizer/plan/planner.c

@@ -2098,52 +2098,6 @@ is_dummy_plan(Plan *plan)
 	return false;
 }
 
-/*
- * Create a bitmapset of the RT indexes of live base relations
- *
- * Helper for preprocess_rowmarks ... at this point in the proceedings,
- * the only good way to distinguish baserels from appendrel children
- * is to see what is in the join tree.
- */
-static Bitmapset *
-get_base_rel_indexes(Node *jtnode)
-{
-	Bitmapset  *result;
-
-	if (jtnode == NULL)
-		return NULL;
-	if (IsA(jtnode, RangeTblRef))
-	{
-		int			varno = ((RangeTblRef *) jtnode)->rtindex;
-
-		result = bms_make_singleton(varno);
-	}
-	else if (IsA(jtnode, FromExpr))
-	{
-		FromExpr   *f = (FromExpr *) jtnode;
-		ListCell   *l;
-
-		result = NULL;
-		foreach(l, f->fromlist)
-			result = bms_join(result,
-							  get_base_rel_indexes(lfirst(l)));
-	}
-	else if (IsA(jtnode, JoinExpr))
-	{
-		JoinExpr   *j = (JoinExpr *) jtnode;
-
-		result = bms_join(get_base_rel_indexes(j->larg),
-						  get_base_rel_indexes(j->rarg));
-	}
-	else
-	{
-		elog(ERROR, "unrecognized node type: %d",
-			 (int) nodeTag(jtnode));
-		result = NULL;			/* keep compiler quiet */
-	}
-	return result;
-}
-
 /*
  * preprocess_rowmarks - set up PlanRowMarks if needed
  */
@@ -2183,7 +2137,7 @@ preprocess_rowmarks(PlannerInfo *root)
 	 * make a bitmapset of all base rels and then remove the items we don't
 	 * need or have FOR [KEY] UPDATE/SHARE marks for.
 	 */
-	rels = get_base_rel_indexes((Node *) parse->jointree);
+	rels = get_relids_in_jointree((Node *) parse->jointree, false);
 	if (parse->resultRelation)
 		rels = bms_del_member(rels, parse->resultRelation);