Fixed #31169 -- Adapted the parallel test runner to use spawn.

Co-authored-by: Valz <ahmadahussein0@gmail.com>
Co-authored-by: Nick Pope <nick@nickpope.me.uk>

tests/postgres_tests/test_bulk_update.py

@@ -1,5 +1,7 @@
 from datetime import date
 
+from django.test import modify_settings
+
 from . import PostgreSQLTestCase
 from .models import (
     HStoreModel,
@@ -16,6 +18,7 @@ except ImportError:
     pass  # psycopg2 isn't installed.
 
 
+@modify_settings(INSTALLED_APPS={"append": "django.contrib.postgres"})
 class BulkSaveTests(PostgreSQLTestCase):
     def test_bulk_update(self):
         test_data = [