fixup! Avoid running database migrations for SimpleTestCase

Author: flaeppe

pytest_django/plugin.py

@@ -560,8 +560,11 @@ def non_debugging_runtest(self) -> None:
 
         if request.cls.databases:
             request.getfixturevalue("django_db_setup")
+            db_unblock = django_db_blocker.unblock()
+        else:
+            db_unblock = contextlib.nullcontext()
 
-        with django_db_blocker.unblock():
+        with db_unblock:
             yield
     finally:
         TestCaseFunction.runtest = original_runtest  # type: ignore[method-assign]