BUG #15352: postgresql FDW error "ERROR: ORDER BY position 0 is not in select list"

The following bug has been logged on the website:

Bug reference: 15352
Logged by: Maksym Boguk
Email address: maxim(dot)boguk(at)gmail(dot)com
PostgreSQL version: 9.6.8
Operating system: Linux
Description:

Hi,

I found strange error with postgresql_fdw used with use_remote_estimate
'true'.

Trimmed test case:

\с postgres
create extension postgres_fdw;
CREATE SERVER test FOREIGN DATA WRAPPER postgres_fdw OPTIONS (
dbname 'postgres',
use_remote_estimate 'true'
);
CREATE USER MAPPING FOR public SERVER test OPTIONS (
"user" 'postgres'
);
IMPORT FOREIGN SCHEMA pg_catalog
LIMIT TO (pg_stat_user_tables)
FROM SERVER test
INTO public;
select *
from pg_catalog.pg_stat_user_tables
join public.pg_stat_user_tables USING (relid)
WHERE
greatest(pg_catalog.pg_stat_user_tables.idx_scan,
public.pg_stat_user_tables.idx_scan)=0;

ERROR: ORDER BY position 0 is not in select list
CONTEXT: Remote SQL command: EXPLAIN SELECT relid, schemaname, relname,
seq_scan, seq_tup_read, idx_scan, idx_tup_fetch, n_tup_ins, n_tup_upd,
n_tup_del, n_tup_hot_upd, n_live_tup, n_dead_tup, n_mod_since_analyze,
last_vacuum, last_autovacuum, last_analyze, last_autoanalyze, vacuum_count,
autovacuum_count, analyze_count, autoanalyze_count FROM
pg_catalog.pg_stat_user_tables ORDER BY 0 ASC NULLS LAST