erp5_upgrader: Use assertItemsEqual when only the order can be ignored

Here, we expect exactly two activities, one of each type, and just do not
rely on these being listed in any order (...in theory, as this is actually
assumed by the next iteration on getMessageList, but this is a separate
issues).

bt5/erp5_upgrader/TestTemplateItem/portal_components/test.erp5.testUpgrader.py

@@ -344,8 +344,8 @@ class TestUpgrader(ERP5TypeTestCase):
 
   def stepCheckNoActivitiesCreated(self, sequence=None):
     portal_activities = self.getActivityTool()
-    self.assertEqual({'Alarm_runUpgrader', 'notify'},
-      {x.method_id for x in portal_activities.getMessageList()})
+    self.assertItemsEqual(['Alarm_runUpgrader', 'notify'],
+      [x.method_id for x in portal_activities.getMessageList()])
     getTitleList = self.getTemplateTool().getInstalledBusinessTemplateTitleList
     self.assertNotIn('erp5_web', getTitleList())
     for message in portal_activities.getMessageList():