Two bugs made the Linux smoke "succeed" with an empty artifact:
- artifact_source was always joined as workdir + '/' + src, so an
absolute source (/opt/ci/output) became /opt/ci/build//opt/ci/output
and was never found — only a non-fatal WARNING was logged.
- `rm -rf output_dir` ran unconditionally; when the build writes
directly into the collect dir (the smoke case: output == source),
it deleted the build output before collection.
Resolve absolute vs workdir-relative; when the source is the output
dir, collect in place without wiping; a missing/empty source is now a
hard failure instead of a silent empty artifact.
Simone
0c68013e87