BUG #16346: pg_upgrade fails on a trigger with a comment

The following bug has been logged on the website:

Bug reference: 16346
Logged by: Alexander Lakhin
Email address: exclusion(at)gmail(dot)com
PostgreSQL version: 12.2
Operating system: Ubuntu 18.04
Description:

When using pg_upgrade on a database with the following contents:
CREATE FUNCTION public.test_event_trigger() RETURNS event_trigger
LANGUAGE plpgsql
AS $$
BEGIN
RAISE NOTICE 'test_event_trigger: % %', tg_event, tg_tag;
END
$$;

CREATE EVENT TRIGGER regress_event_trigger3 ON ddl_command_start
EXECUTE PROCEDURE public.test_event_trigger();

COMMENT ON EVENT TRIGGER regress_event_trigger3 IS 'test comment';

I get:
Restoring global objects in the new cluster ok
Restoring database schemas in the new cluster
postgres
*failure*

Consult the last few lines of "pg_upgrade_dump_14174.log" for
the probable cause of the failure.
Failure, exiting

pg_upgrade_dump_14174.log contains:
command: "/src/postgres/tmp_install/usr/local/pgsql/bin/pg_restore" --host
/src/postgres --port 50432 --username postgres --clean --create
--exit-on-error --verbose --dbname template1 "pg_upgrade_dump_14174.custom"
>> "pg_upgrade_dump_14174.log" 2>&1
pg_restore: connecting to database for restore
pg_restore: dropping DATABASE PROPERTIES postgres
pg_restore: dropping DATABASE postgres
pg_restore: creating DATABASE "postgres"
pg_restore: connecting to new database "postgres"
pg_restore: connecting to database "postgres" as user "postgres"
pg_restore: creating COMMENT "DATABASE "postgres""
pg_restore: creating DATABASE PROPERTIES "postgres"
pg_restore: connecting to new database "postgres"
pg_restore: connecting to database "postgres" as user "postgres"
pg_restore: creating pg_largeobject "pg_largeobject"
pg_restore: creating FUNCTION "public.test_event_trigger()"
pg_restore: creating COMMENT "EVENT TRIGGER "regress_event_trigger3""
pg_restore: while PROCESSING TOC:
pg_restore: from TOC entry 3705; 0 0 COMMENT EVENT TRIGGER
"regress_event_trigger3" postgres
pg_restore: error: could not execute query: ERROR: event trigger
"regress_event_trigger3" does not exist
Command was: COMMENT ON EVENT TRIGGER "regress_event_trigger3" IS 'test
comment';

It looks like the commit 4c40b27b broke this.