Removed unneeded override_system_checks

Refs #23685.

tests/test_runner/tests.py

@@ -11,7 +11,6 @@ from django.core.management import call_command
 from django.db.backends.dummy.base import DatabaseCreation
 from django.test import runner, TestCase, TransactionTestCase, skipUnlessDBFeature
 from django.test.testcases import connections_support_transactions
-from django.test.utils import override_system_checks
 from django.utils import six
 
 from admin_scripts.tests import AdminScriptTestCase
@@ -225,9 +224,6 @@ class Sqlite3InMemoryTestDbs(TestCase):
 
     available_apps = []
 
-    # `setup_databases` triggers system check framework, but we do not want to
-    # perform checks.
-    @override_system_checks([])
     @unittest.skipUnless(all(db.connections[conn].vendor == 'sqlite' for conn in db.connections),
                          "This is an sqlite-specific issue")
     def test_transaction_support(self):