pgsql: Ensure standby promotion point in 043_wal_replay_wait.pl

Ensure standby promotion point in 043_wal_replay_wait.pl

This commit ensures standby will be promoted at least at the primary insert
LSN we have just observed.  We use pg_switch_wal() to force the insert LSN
to be written then wait for standby to catchup.

Reported-by: Alexander Lakhin
Discussion: https://postgr.es/m/1d7b08f2-64a2-77fb-c666-c9a74c68eeda%40gmail.com

Branch
------
master

Details
-------
https://git.postgresql.org/pg/commitdiff/2520226c953c0b443791a185a8d1fb8b71d9fe9e

Modified Files
--------------
src/test/recovery/t/043_wal_replay_wait.pl | 6 ++++++
1 file changed, 6 insertions(+)