tests: remove jsl tests

This linter is too old and no longer relevant
7 jobs for master in 0 seconds
Status Job ID Name Coverage
  External
failed ERP5.CodingStyleTest-Master

00:37:51

failed ERP5.PerformanceTest-Master

00:28:55

failed ERP5.UnitTest-Master

01:24:59

failed ERP5.UnitTest-Zope2

01:53:43

passed SlapOS.Eggs.UnitTest-Master.Python2

00:13:36

passed SlapOS.Eggs.UnitTest-Master.Python3

00:14:51

passed Wendelin.UnitTest-Master

00:36:43