pgsql: Remove test from commit fa2e874946.

Remove test from commit fa2e874946.

The fix itself is fine, but the test revealed other problems related
to parallel query that are not easily fixable. Remove the test for
now to fix the buildfarm.

Discussion: https://postgr.es/m/88825.1691665432@sss.pgh.pa.us
Backpatch-through: 11

Branch
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REL_12_STABLE

Details
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https://git.postgresql.org/pg/commitdiff/01bc42634e59e1e746eec236ac17247bdcc228e9

Modified Files
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src/test/isolation/expected/search-path-inval.out | 97 -----------------------
src/test/isolation/isolation_schedule             |  1 -
src/test/isolation/specs/search-path-inval.spec   | 59 --------------
3 files changed, 157 deletions(-)