Various gcovr clean-ups
This primarily fixes gcov failures. Other gcov CI job clean-up were added as well.
Validation job: https://gitlab.isc.org/isc-projects/bind9/-/jobs/2923791
Supersedes !7097 (closed).
This primarily fixes gcov failures. Other gcov CI job clean-up were added as well.
Validation job: https://gitlab.isc.org/isc-projects/bind9/-/jobs/2923791
Supersedes !7097 (closed).