Run Javascript tests with node/puppeteer as well as Phantomjs

followup to https://github.com/matomo-org/matomo/pull/14421

It seems like the JS tests are still using Phantomjs (which isn't maintained anymore).

https://github.com/matomo-org/travis-scripts/blob/e955829a58a5a6af00a40737c663ede98eef5dcb/travis.sh#L28-L33

It might be useful to also use Chromium/Pupeteer there to make sure Matomo JS still works in modern browsers.