tests: Restrict pg_locks queries in advisory_locks.sql to current database
Otherwise testing an existing installation can fail, if there are other locks,
e.g. from one of the isolation tests.
Reviewed-by: Michael Paquier <michael@paquier.xyz>
Discussion: https://postgr.es/m/
20221003234111.4ob7yph6r4g4ywhu@awork3.anarazel.de