Fix EZP-20530: Fix incomplete unit & integration tests part 3

This PR resolves issue https://jira.ez.no/browse/EZP-20530.

Two tests for Legacy IO handler are marked as skipped instead of incomplete, as the functionality tested by the base tests is not supported by it.

One integration test for ContentTypeService is enabled by removing `markTestIncomplete` as the test was found to be correct.

This leaves only one incomplete test which is about throwing `BadStateException` in `Repository:canUser()` method. As the behavior can not be tested on given fixture, marking it as incomplete is correct.

While testing one problem was found: https://jira.ez.no/browse/EZP-21014