Therefore, all Test Components are now ERP5TypeLiveTestCase. For backward
compatibility sake, just modify Test Component class bases to
ERP5TypeLiveTestCase, likewise runLiveTest.

This means that tests ran through runUnitTest and from Live Tests ERP5 UI would
behave exactly the same, contrary to the implementation before Test Components.

Also, move a method called in one of ERP5TypeTypeMixin method from
ERP5TypeTestCaseCommandLine.