pgsql: Fix race condition in recently-added TAP test for recoveryconsi

Fix race condition in recently-added TAP test for recovery consistency

A couple of queries are run on the primary to create and fill in a test
table, which gets checked on the standby afterwards.  However the test
was not waiting for the confirmation that the necessary records have
been replayed on the standby, leading to spurious failures.

Per buildfarm member loach.  Thanks to Thomas Munro for the report and
Tom Lane for the failure analysis.

Discussion: https://postgr.es/m/CA+hUKGLUpqG52xtriUz5RpmeKPoEfNxNc-CginG+Cx+X2-Ycew@mail.gmail.com

Branch
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master

Details
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https://git.postgresql.org/pg/commitdiff/364298be22090769da14aa749fe730cf16ed3c2c

Modified Files
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src/test/recovery/t/016_min_consistency.pl | 4 ++++
1 file changed, 4 insertions(+)