Add test for websocket origin in a worker

[Manishearth]

We should add a .worker.js test that ensures that a websocket's origin is correctly set when used from a worker.

.worker.js tests are automatically run in a worker context. and look like this

We already have https://github.com/Manishearth/servo/blob/ws-worker/tests/wpt/web-platform-tests/websockets/opening-handshake/003.html to test the origin; we need to write a similar test in a .worker.js context (use importScript instead of script tags, call done() when the test is over)

Be sure to add it to the manifest like so. The test can be run with ./mach test-wpt /websockets/name-of-test.worker.

[g-k]

Not sure if a couple of the links are broken for anyone else, but these work for me:

https://github.com/Manishearth/servo/blob/master/tests/wpt/web-platform-tests/websockets/opening-handshake/003.html

https://github.com/Manishearth/servo/blob/master/tests/wpt/web-platform-tests/websockets/Send-data.worker.js

[Manishearth]

Yeah, so the former is an example of a test which tests the websocket's origin, the latter is an example of a .worker.js test which runs from a worker (but doesn't test the origin). This issue is asking for a test that does both -- runs a websocket in a worker scope and checks that the origin is correctly set.

[g-k]

Gotcha, I can pick this up if no one else is working on it.