pgsql: Drop test view when done with it.

Drop test view when done with it.

The view just added by commit 53fe7e6cb decompiles differently
in v15 than HEAD (presumably as a consequence of 47bb9db75).
That causes failures in cross-version upgrade testing.

We could teach AdjustUpgrade.pm to compensate for that, but it
seems less painful to just drop the view after we're done with it.

Per buildfarm.

Branch
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master

Details
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https://git.postgresql.org/pg/commitdiff/71a75626d5271f2bcdbdc43b8c13065c4634fd9f

Modified Files
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contrib/postgres_fdw/expected/postgres_fdw.out | 3 +++
contrib/postgres_fdw/sql/postgres_fdw.sql      | 4 ++++
2 files changed, 7 insertions(+)