Thread: pgsql: Close race condition in slot_creation_error.spec.

Close race condition in slot_creation_error.spec.

Use the pattern from detach-partition-concurrently-3.spec.  Per
buildfarm member wrasse.

Reviewed by Kyotaro Horiguchi and Andres Freund.

Discussion: https://postgr.es/m/20220318072837.GC2739027@rfd.leadboat.com

Branch
------
master

Details
-------
https://git.postgresql.org/pg/commitdiff/e186f56f9c6ead4ef65848ae6c499f9949b12625

Modified Files
--------------
.../test_decoding/expected/slot_creation_error.out   | 20 +++++++++++---------
contrib/test_decoding/specs/slot_creation_error.spec |  4 ++--
2 files changed, 13 insertions(+), 11 deletions(-)