Upstream service worker "register" tests to WPT

**register-default-scope**

This test exists in both WPT and the Chromium project tree. Because they
differ only in implementation details of the testing infrastructure, the
Chromium-specific version may be removed without affecting test coverage
in the Chromium project.

**register-link-element**

This test was previously re-located to the Web Platform Tests project
[1], but its corresponding "expectations" file was mistakenly persisted.
Remove that file.

[1] See commit e46007715a723c2219f49db6199f1af09cbbc7db in the Chromium
    project

**register-same-scope-different-script-url**

This test exists in both WPT and the Chromium project tree. The WPT
version is slightly weaker because it accounts for a condition that is
not possible according to the latest version of the Service Workers
specification [2].

> # Install
>
> [...]
>
> 17. Run the Update Registration State algorithm passing registration,
>     "installing" and null as the arguments.
> 18. Run the Update Worker State algorithm passing registration’s
>     waiting worker and installed as the arguments.
> 19. Invoke Finish Job with job.
> 20. Wait for all the tasks queued by Update Worker State invoked in
>     this algorithm have executed.
> 21. Invoke Try Activate with registration.

Due to step 20, worker activation does not occur until all prior tasks
(which includes microtasks such as the Promise handler microtask created
in the test's body) have executed.

Remove the conditional logic from the WPT version and remove the
Chromium test file.

[2] https://w3c.github.io/ServiceWorker/#installation-algorithm,
    retrieved on 2017-05-16

**register-wait-forever-in-install-worker**

The Web Platform Tests project maintains a more rigorous version of this
test, but because that version currently fails in Chromium, this version
cannot be removed without negatively effecting test coverage.

Re-name the test file and add an in-line comment to document the test's
deprecated status.

**register-foreign-fetch-error**

Update URLs to suitable values for the Web Platform Tests project.

BUG=688116, 723037
R=falken@chromium.org

Review-Url: https://codereview.chromium.org/2892473003
Cr-Commit-Position: refs/heads/master@{#472636}
8 files changed