inline test suite fails in GitLab CI

One of the full build logs can be found here: https://gitlab.isc.org/isc-projects/bind9/-/jobs/777/raw

But more distros and archs are affected: https://gitlab.isc.org/isc-projects/bind9/pipelines/54

The inline test fails at several subtests when running inside GitLab CI:

S:inline:Mon Feb 12 15:00:01 UTC 2018
T:inline:1:A
A:System test inline
I:checking that rrsigs are replaced with ksk only (1)
I:checking that the zone is signed on initial transfer (2)
I:failed
[...]
I:exit status: 1
R:FAIL