[1.7.x] Fixed broken tests on Oracle after 5853c87a45.

Oracle doesn't have a `BEGIN` statement so the test would
fail.

Refs #23303

Backport of 54164b814c from master.

tests/migrations/test_commands.py

@@ -6,7 +6,7 @@ import os
 import shutil
 
 from django.apps import apps
-from django.db import models
+from django.db import connection, models
 from django.core.management import call_command, CommandError
 from django.db.migrations import questioner
 from django.test import override_settings, override_system_checks
@@ -96,9 +96,9 @@ class MigrateTests(MigrationTestBase):
         # Make sure the output is wrapped in a transaction
         stdout = six.StringIO()
         call_command("sqlmigrate", "migrations", "0001", stdout=stdout)
-        output = stdout.getvalue().lower()
-        self.assertIn("begin;", output)
-        self.assertIn("commit;", output)
+        output = stdout.getvalue()
+        self.assertIn(connection.ops.start_transaction_sql(), output)
+        self.assertIn(connection.ops.end_transaction_sql(), output)
 
         # Test forwards. All the databases agree on CREATE TABLE, at least.
         stdout = six.StringIO()