Test ranges created during unit tests have their parameters such as base RID, base ID or range size hardcoded.

When running unit test suite on a IPA instance with trust already estabilished, it might happen that these tests ranges will not create during the tests due to overlap with the trusted range. This provides us with a incorrect set of results for the plugin.

Modify the idrange plugin tests so that the space for the ranges is allocated dynamically, making sure there's no overlap with the existing ranges.