CI: Include a job index in names of collected artifacts
And include "extra" Linux elements to further disambiguate
archive names.
The current naming of artifacts is inadequate when it comes
to files whose differing name-parts only come from array
values, as arrays are not automatically converted to string.
For example, both artifacts for failing "socketserver" and
"no_x11" CI jobs will claim the same name, and whichever job
finishes last is allowed to overwrite another matching name
artifact.