Finish the CouchDB test matrix

@dickolsson We need to do this on entity denormalization, and I think it is not possible to it in `\Drupal\relaxed\Normalizer\RevisionInfoItemListNormalizer`. I can add a check if the `revs_info` or the `open_revs` parameters is available in `\Drupal\relaxed\Normalizer\ContentEntityNormalizer`. What do you think?