pgsql: Simplify FK-to-partitioned regression test query

Simplify FK-to-partitioned regression test query

Avoid a join between relations having the FK to detect FK violation.
The planner might optimize this considering the PK must exist on the
referenced side at some point, effectively masking a bug this test
tries to detect.

Tom Lane and Jehan-Guillaume de Rorthais
Discussion: https://postgr.es/m/467.1581270529@sss.pgh.pa.us

Branch
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master

Details
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https://git.postgresql.org/pg/commitdiff/b2304a71748a3e664a1b8354d746f28c38aaa816

Modified Files
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src/test/regress/expected/foreign_key.out | 14 ++++++++------
src/test/regress/sql/foreign_key.sql      |  6 ++----
2 files changed, 10 insertions(+), 10 deletions(-)