erp5_*_renderjs_ui_test: stabilize test

8 jobs for master in 0 seconds
Status Job ID Name Coverage
  External
passed ERP5.CodingStyleTest-Master

00:51:23

failed ERP5.PerformanceTest-Master

00:24:14

failed ERP5.UnitTest-Master

01:00:46

failed ERP5.UnitTest-Master.Medusa

02:13:31

passed SlapOS.Eggs.UnitTest-Master.Python2

00:26:35

passed SlapOS.Eggs.UnitTest-Master.Python3

00:14:43

failed ERP5.UnitTest-Master

03:50:19

canceled ERP5.UnitTest-Master