some tests in websockets/constructor does not refer constants.js

TestTWF Tokyo Meetup : needs review

I found that several tests in websockets/constructor doesn't refer constants.js for new WebSocket(). (location.hostname or specific site)

For above, it is hard to check in local development while switch DOMAIN_FOR_WS_TESTS to "w3c-test.org" in constants.js.

So, I've fixed to refer constants.js completely for tests in constructor directory.