Make hardening work correctly even for named SQLite DBs, also make the related test test named SQLite DBs instead of just MySQL (the SQLite dataset fails when the DatabaseTenancyBootstrapper changes get reverted).
"database tenancy bootstrapper throws an exception if DATABASE_URL is set" was failing with the null $databaseUrl because the tenant DB was never created. This test was ignored during test runs because the test file lacked the 'Test' suffix.