pgsql: Stabilize regression test from c0962a113.

Stabilize regression test from c0962a113.

Per buildfarm.

Co-authored-by: Alena Rybakina <a.rybakina@postgrespro.ru>
Co-authored-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: /messages/by-id/srnuqlttuimzmvoulhsrbgvj4vnul6b65osswvua7sfkqsvmuy@yg7apybpxp34

Branch
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master

Details
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https://git.postgresql.org/pg/commitdiff/3ba2cdaa45416196fadc7163998cda7b4e07e7d7

Modified Files
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src/test/regress/expected/subselect.out | 37 +++++++++++++++++----------------
src/test/regress/sql/subselect.sql | 8 +++----
2 files changed, 23 insertions(+), 22 deletions(-)