pgsql: pg_stat_statements: Remove duplicated tests for SET statements

pg_stat_statements: Remove duplicated tests for SET statements

This looks like a copy-paste mistake introduced in de2aca288569, that
has added checks for more patterns of SET statements while ignoring the
original test block that existed.

Backpatch down to where this has been introduced, as this shaves some
cycles.

Author: Sergei Kornilov
Discussion: https://postgr.es/m/5689421699428803@mail-sendbernar-production-main-46.myt.yp-c.yandex.net
Backpatch-through: 16

Branch
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REL_16_STABLE

Details
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https://git.postgresql.org/pg/commitdiff/179c4639cf1dcbe54f3469d7f44a11f172332893

Modified Files
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contrib/pg_stat_statements/expected/utility.out | 27 -------------------------
contrib/pg_stat_statements/sql/utility.sql      | 13 ------------
2 files changed, 40 deletions(-)