BUG #19018: high memory usage and "stack depth limit exceeded", with GiST index on ltree

The following bug has been logged on the website:

Bug reference: 19018
Logged by: Joseph Silva
Email address: dull(dot)bananas0(at)gmail(dot)com
PostgreSQL version: 17.5
Operating system: Fedora
Description:

If I run this, then the postgres process's memory usage approaches 6 GB, and
the insertion when
i=253 fails with "stack depth limit exceeded":

```
CREATE EXTENSION ltree;

CREATE TABLE comment (path ltree);

CREATE INDEX ON comment USING gist (path);

DO $$
DECLARE
i int := 1;
p text := '0';
BEGIN
WHILE i < 1000 LOOP
p := p || '.' || i::text;
i := i + 1;
INSERT INTO comment (path) VALUES (p::ltree);
COMMIT;
END LOOP;
END
$$;
```

If index creation is delayed until after insertions, then the insertions
succeed but index creation
fails.