recoveryCheck test failure on flaviventris

I noticed this recoveryCheck test failure on flaviventris after
pushing commit 3b35f9a4c (Fix an incorrect check in get_memoize_path).

### Reloading node "standby"
# Running: pg_ctl --pgdata xxx/pgdata reload
server signaled
### Restarting node "standby"
# Running: pg_ctl --wait --pgdata xxx/pgdata --log xxx.log restart
waiting for server to shut down ... failed
pg_ctl: server does not shut down
# pg_ctl restart failed; see logfile for details: xxx.log
# Postmaster PID for node "standby" is 63577
[02:09:29.767](364.847s) Bail out!  pg_ctl restart failed

I'm not convinced this failure is related to 3b35f9a4c; it seems
unlikely that just changing how Memoize paths are created would cause
it.

Does anyone have any insights into what might be going on?

Thanks
Richard