spurious pg_amcheck test failure

Hi,

In a rare CI failure I just noticed:

https://cirrus-ci.com/task/4901437240508416
https://api.cirrus-ci.com/v1/artifact/task/4901437240508416/testrun/build/testrun/pg_amcheck/002_nonesuch/log/regress_log_002_nonesuch

[11:38:06.031](0.000s) # Failed test 'schema exclusion pattern overrides all inclusion patterns stderr /(?^:pg_amcheck: warning: skipping database "template1": amcheck is not installed)/'
# at /Users/admin/pgsql/src/bin/pg_amcheck/t/002_nonesuch.pl line 400.
[11:38:06.031](0.000s) # 'pg_amcheck: warning: skipping database "another_db": amcheck is not installed
# '
# doesn't match '(?^:pg_amcheck: warning: skipping database "template1": amcheck is not installed)'
[11:38:06.031](0.000s) not ok 107 - schema exclusion pattern overrides all inclusion patterns stderr /(?^:pg_amcheck: error: no relations to check)/
[11:38:06.031](0.000s) # Failed test 'schema exclusion pattern overrides all inclusion patterns stderr /(?^:pg_amcheck: error: no relations to check)/'
# at /Users/admin/pgsql/src/bin/pg_amcheck/t/002_nonesuch.pl line 400.
[11:38:06.031](0.000s) # 'pg_amcheck: warning: skipping database "another_db": amcheck is not installed
# '
# doesn't match '(?^:pg_amcheck: error: no relations to check)'

I don't really understand how there can be an *occasional* reordering of the
database list - afaict the pg_amcheck query has an ORDER BY that should
prevent that?
") AS combined_records"
"\nORDER BY pattern_id NULLS LAST, datname");

Greetings,

Andres Freund