Fixed #25357 -- Database deduplication on Oracle.

    mirrors = []

    for signature, (db_name, aliases) in test_databases.items():

        test_db_name = None

        first_alias = None

        # Actually create the database for the first connection

        for alias in aliases:

            connection = connections[alias]

            if test_db_name is None:

                test_db_name = connection.creation.create_test_db(

            old_names.append((connection, db_name, first_alias is None))

            if first_alias is None:

                first_alias = alias

                connection.creation.create_test_db(

                    verbosity,

                    autoclobber=not interactive,

                    keepdb=keepdb,

                    serialize=connection.settings_dict.get("TEST", {}).get("SERIALIZE", True),

                )

                destroy = True

            else:

                connection.settings_dict['NAME'] = test_db_name

                destroy = False

            old_names.append((connection, db_name, destroy))

                connections[alias].creation.set_as_test_mirror(

                    connections[first_alias].settings_dict)

    for alias, mirror_alias in mirrored_aliases.items():

        mirrors.append((alias, connections[alias].settings_dict['NAME']))