Update inline system test, zone 'retransfer3.'

Update inline system test, zone 'retransfer3.'

The zone 'retransfer3.' tests whether zones that 'rndc signing
-nsec3param' requests are queued even if the zone is not loaded.

The test assumes that if 'rndc signing -list' shows that the zone is
done signing with two keys, and there are no NSEC3 chains pending, the
zone is done handling the '-nsec3param' queued requests. However, it
is possible that the 'rndc signing -list' command is received before
the corresponding privatetype records are added to the zone (the records
that are used to retrieve the signing status with 'rndc signing').

This is what happens in test failure
https://gitlab.isc.org/isc-projects/bind9/-/jobs/2722752.

The 'rndc signing -list retransfer3' is thus an unreliable check.
It is simpler to just remove the check and wait for a certain amount
of time and check whether ns3 has re-signed the zone using NSEC3.