Fix one of the tests introduced in commit
52e4f0cd47.
In the Publisher-Subscriber setup, after performing a DML operation on the
publisher, we need to wait for it to be replayed on the subscriber before
querying the same data on the subscriber. One of the tests missed the wait
step.
As per buildfarm.
Author: Peter Smith
Discussion: https://postgr.es/m/CAHut+Pv=e9Qd1TSYo8Og6x6Abfz3b9_htwinLp4ENPgV45DACQ@mail.gmail.com