In pmb.helpers.package.get(), we are differentiating between packages
that do not exist at all, and packages that do not exist for the
specified architecture. Make sure to actuallyy download the foreign arch
APKINDEX files, before trying to find the packages in there. Otherwise
the "could not find aport, and could not find this package in any
APKINDEX" package would appear.
We ran into this when testing on sr.ht, because pmbootstrap runs on a
fresh install every time, where no old APKINDEX files are present
(which would work around the bug).
This was meant to be part of the previous commit already, and was
tested, but it was not submitted correctly. So here it is as separate
commit straight to master. It is trivial anyway.