To support no-zip flag for artifacts
Do not zip the artifact if it is not useful.
Sometimes, the build script generates a single zip file (due to some issues of gitlab: https://gitlab.com/gitlab-org/gitlab-ci-multi-runner/issues/1057#note_19230975).
However, gitlab re-zip artifact even it is a single zip file.
- Do not zip artifacts if it is a single file.
- Support no-zip flag for artifacts