regress: fix test instability

Alvaro Herrera <alvherre@alvh.no-ip.org>

Commit: 4ad4c1f419477a3a450ecaa6b3a367c227a7df66
Author: Alvaro Herrera <alvherre@alvh.no-ip.org>
Date: 2022-08-05T09:55:52Z
Releases: 12.12
regress: fix test instability

Having additional triggers in a test table made the ORDER BY clauses in
old queries underspecified.  Add another column there for stability.

Per sporadic buildfarm pink.

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