CI: gitlab: Collect pytest artifacts

CI: gitlab: Collect pytest artifacts

Copy build artifacts for all test.py tests, so they show up in
artifacts storage for later inspection. The test.py tests output
in CI is basically useless, but it is far more useful in the html
output for analysis and debugging.

Reviewed-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Tom Rini <trini@konsulko.com>
Suggested-by: Simon Glass <sjg@chromium.org>
Signed-off-by: Marek Vasut <marek.vasut+renesas@mailbox.org>