Add test for allowing update CDS/CDNSKEY

Add test for allowing update CDS/CDNSKEY

Add tests to the nsupdate system test to make sure that CDS and/or
CDNSKEY that match an algorithm in the DNSKEY RRset are allowed. Also
add tests that updates are rejected if the algorithm does not match.

Remove the now redundant test cases from the dnssec system test.

Update the checkzone system test: Change the algorithm of the CDS and
CDNSKEY records so that the zone is still rejected.