Test database is failing on release-12.1 + REL_16_STABLE

[0844b396](https://github.com/postgres/postgres/commit/0844b3968985447ed0a6937cfc8639e379da2fe6) adds new test `database`. It fails when running `make check-vanilla` on release-12.1 with the following diff
```
@@ -1,14 +1,15 @@
CREATE DATABASE regression_tbd
ENCODING utf8 LC_COLLATE "C" LC_CTYPE "C" TEMPLATE template0;
ALTER DATABASE regression_tbd RENAME TO regression_utf8;
ALTER DATABASE regression_utf8 SET TABLESPACE regress_tblspace;
+ERROR: unrecognized ALTER DATABASE option: tablespace
ALTER DATABASE regression_utf8 RESET TABLESPACE;
ALTER DATABASE regression_utf8 CONNECTION_LIMIT 123;
-- Test PgDatabaseToastTable. Doing this with GRANT would be slow.
BEGIN;
UPDATE pg_database
SET datacl = array_fill(makeaclitem(10, 10, 'USAGE', false), ARRAY[5e5::int])
WHERE datname = 'regression_utf8';
-- load catcache entry, if nothing else does
ALTER DATABASE regression_utf8 RESET TABLESPACE;
ROLLBACK;
```
This problem does not occur on main because `alter database set TABLESPACE ` support was added in main by #7253