officejs_support_request_ui_test: adjust test for Distributed Cache sessions

With distributed caches, portal_caches.clearAllCache() does not clear cache, so
using ERP5Site_cleanupSupportRequestUITestDataSet is not enough to flush the
"last comment" from portal sessions, so we need to delete explicitly the
session - and also commit the transaction because distributed caches are also
transactional.

bt5/erp5_officejs_support_request_ui_test/TestTemplateItem/portal_components/test.erp5.testSupportRequest.py

@@ -64,6 +64,8 @@ class SupportRequestTestCase(ERP5TypeTestCase, object):
     self.portal.person_module.manage_delObjects(
         [self.user.getId()])
     self.assertEqual(self.portal.ERP5Site_cleanupSupportRequestUITestDataSet(), 'Done.')
+    self.portal.portal_sessions.manage_delObjects(
+      ['support_request_module/erp5_officejs_support_request_ui_test_support_reuqest_001.latest_comment'])
     self.tic()
 
   def createUserAndLogin(self):