service worker: Prepare sandboxed-iframe-navigator-serviceworker.html for upstreaming

To help reviewing this patch first changes the test and another one will
move it to external/wpt.

The subject matter seems fine for WPT although the final promise_test was
intended as just a crash test and Chromium's behavior is not totally
matching the spec. I wrote the expectation according to my interpretation
of the spec and nhiroki's TODO.

Bug: 688116, 532855, 486308
Change-Id: Ia6b9b178c21691a1abca3c60c7fc38ee86ea0989
Reviewed-on: https://chromium-review.googlesource.com/761270
Commit-Queue: Matt Falkenhagen <falken@chromium.org>
Reviewed-by: Hiroki Nakagawa <nhiroki@chromium.org>
Reviewed-by: Tsuyoshi Horo <horo@chromium.org>
Cr-Commit-Position: refs/heads/master@{#515878}
3 files changed