The dependency on java was introduced in 2012 (c021cf52d8) to start
Sauce-Connect from sauce labs.
Probably at the time it was a runtime dependency, but it is no longer the case
today. It is possible that java was already not needed when db003a1460 changed
from downloading Sauce-Connect-latest.zip to sc-latest-linux.tar.gz.
Moreover, I am quite sure tests/frontend/travis/sauce_tunnel.sh no longer works
today, because tests/frontend/travis/sauce_tunnel.sh downloads from an url that
gives HTTP/404 now: sc-latest-linux.tar.gz if no longer a valid file name, we
would need to explicitly download a specific version.
