Web Platform Tests

[kflansburg]

• [X] [PR #2585] Initial scaffolding (bazel test autodiscovery, test harness, a couple of URL test cases)
• [X] [PR #3002] url tests
• [X] [PR #3030] urlpattern tests
• [ ] Autogenerate -test.js file so that we don't miss out on new WPT cases as they're added. Config in -config.js.
• [ ] Document how to add wpt test suites

[anonrig]

@npaun It seems assert_throws_js implementation is wrong. Here's the Node.js implementation: https://github.com/nodejs/node/blob/8807549ed9f6eaf6842ae56b8ac55ab385951636/test/fixtures/wpt/resources/testharness.js#L2046

[anonrig]

Additional issue: @npaun If a test is in expected_failures but if it doesn't fail, we should also throw an error.

[npaun]

Yep that's an excellent idea.