To ensure that we can update from very old releases, add a test with a
fixed old release, here the Stable release that introduced arm64
support to have the same test logic for both architectures.
qemu_update vendor test was downloading a wrong LTS image when it was
testing the old LTS image. This is because it was using a current
symlink, which for LTS channel will always point to the new LTS. Old
LTS is available under current-${YEAR} symlink. We can get the
information about year from the lts-info file.
For now we had only "developer" images in the new pipeline.
Based on the git tag like "alpha-1234.0.0" set the channel (group) for
the image and also use this logic when finding the channel in the QEMU
update test.
The kola update test was missing. It is performed as update from the
old image to the newly built payload to ensure that the new image is
compatible for old clients.
