Update web-platform-tests expectations.
Merge pull request #2825 from Ms2ger/wpt-expectations

Update web-platform-tests expectations.
Merge pull request #2839 from Ms2ger/globals

Introduce abstractions for global scopes; r=Manishearth,larsberg
Implement a stub Worker interface.

Part of #2811.
Implement stub classes for WorkerGlobalScope and DedicatedWorkerGlobalScope.

Part of #2811.
Add worker scope variants to the Global enums.
Parse the URL passed to the Worker constructor.
Spawn a thread for workers.
Add a constructor for DedicatedWorkerGlobalScope.
Load scripts in workers.
Store the JSContext in a field on the worker global scope.
Implement global.console in workers.
Support Worker globals in global_object_for_js_object.