Fix pgbench TAP test.
Bildfarm member prairiedog reported a pgbench TAP test failure after
commit:
4a39f87acd6e681e5ded1239391d8a92645b43d6. This commit attempts
to fix some copy&paste errors introduced in the previous commit.
Author: Yugo Nagata
Reported-by: Tom Lane
Discussion: https://postgr.es/m/
2775989.
1648060014%40sss.pgh.pa.us