Enhance crossref test to highlight inconsistencies between crossrefs recovered from restored project and crossrefs recovered from freshly retrieved accessions

JAL-3705 reports a difference between the naming and availability of crossrefs for protein products recovered from an ENA entry that is retrieved and saved as a project and the crossrefs recovered from the ENA entry immediatly after retrieval.

The operational CrossRef2xmlTests.testRetrieveAndShowCrossref test needs to be modified to detect *differences* between the retrieved sets of crossrefs after restoring from project.