Replace fedora-ci.koji-build.tier0.functional with
baseos-qe.koji-build.scratch-build.validation.
The former testcase, fedora-ci.koji-build.tier0.functional, aims to
perform the kernel rebuild on a fedora CI test system, not in koji.
The latter, baseos-qe.koji-build.scratch-build.validation is supposed
to run a kernel rebuild in a side-tag koji buildroot, which is closer
to a real kernel rebuild.
This commit sets baseos-qe.koji-build.scratch-build.validation as
the default kernel rebuild gating test for binutils.
Introduce baseos-qe.koji-build.scratch-build.validation as a new
gating test for binutils. The test makes sure that the binutils
update under test doesn't break the kernel build process. The
testing kernel build happens in koji in a side-tag buildroot
containing the binutils build under test.
The source code of this new testcase lives here:
https://github.com/fedora-ci/scratch-build-test
In case of a failure that is considered a false positive, the test
result can be waived using Bodhi this way:
https://docs.fedoraproject.org/en-US/ci/gating/#_waive
Sanity/rebuild-kernel-and-reboot is imported from RHEL's
tests/binutils/Sanity/rebuild-kernel-and-reboot (as of commit c5bc77c).
It needs some adaptations first before running in Fedora.
