Issue #3250999: Remove orphaned database_drivers test fixtures for the legacy...
Issue #3250999: Remove orphaned database_drivers test fixtures for the legacy DRUPAL_ROOT/drivers layout
The 'custom' and 'core' fixture directories under core/tests/fixtures/database_drivers/ simulated database drivers placed directly in DRUPAL_ROOT/drivers, a layout that is no longer supported now that all core and contrib database drivers are provided by modules. No test file references these fixtures anymore; the only fixture still in use is 'module', which represents the current, supported driver location.
Closes #3250999