named-checkzone and named-checkconf -z silently skipped the
missing-glue check for any NS name that had already triggered an
extra-AAAA-glue warning, so zones missing required A glue could pass
validation and be deployed with broken delegations.
Merge branch 'ondrej/check-tool-err-glue-code-collision' into 'main'
See merge request isc-projects/bind9!11899