pgsql: Stabilize regression tests introduced by 259c96fa8f

Stabilize regression tests introduced by 259c96fa8f

Add the ORDER BY clause to new queries to avoid ordering ambiguity.

Per buildfarm member rorqual.

Branch
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master

Details
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https://git.postgresql.org/pg/commitdiff/449cdcd486bfc6864e4fa6784cc1526a94fe69db

Modified Files
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src/test/regress/expected/partition_merge.out | 5 +++--
src/test/regress/expected/partition_split.out | 3 ++-
src/test/regress/sql/partition_merge.sql      | 3 ++-
src/test/regress/sql/partition_split.sql      | 3 ++-
4 files changed, 9 insertions(+), 5 deletions(-)