fixup! Add a test to check whether update of a part of repeated elements works.

this accidentally removed the assertions from test_insert_element_with_same_id

src/tests/erp5diff_test_suite.py

@@ -1183,6 +1183,7 @@ class TestERP5Diff(unittest.TestCase):
   </xupdate:insert-after>
 </xupdate:modifications>
 """
+    self._assertERP5DiffWorks(old_xml, new_xml, expected_result_string)
 
   def test_part_of_repeated_elements_updated(self):
     """32. Update a part of repeated elements