Give the JS tests their own exit status
Give the JS tests their own exit status

It's useful to have something that points to the
testsuite that's being run, as mentioned in:

https://github.com/alphagov/digitalmarketplace-buyer-frontend/pull/159#discussion_r39135917

alphagov/digitalmarketplace-supplier-frontend,alphagov/digitalmarketplace-supplier-frontend,alphagov/digitalmarketplace-supplier-frontend,alphagov/digitalmarketplace-supplier-frontend