Upstream service wrkr "HTTP to HTTPS" tests to WPT

**http-to-https-redirect-and-register**

The Web Platform Tests project's infrastructure can only provide secure
contexts through the use of the HTTPS protocol. This restriction
precludes the strategy used by this test because an HTTPS-origin page
cannot load an HTTP-origin iframe.

Introduce a related test that may run in the WPT infrastructure: one
that creates browsing contexts via `window.open`. Update the surrounding
logic to accomodate this alteration. Additionally, update URLs to
suitable values for the WPT project, using the `base_path` utility
function as per convention there.

Because the new version differs substantially, the original version
cannot be removed without decreasing test coverage. Persist the original
version of the test within the Chromium project, and document the
rational for doing so.

Update both versions to include "use strict" directives for all script
bodies and to avoid including unnecessary script resources.

BUG=688116, 522900
R=falken@chromium.org

Review-Url: https://codereview.chromium.org/2911073002
Cr-Commit-Position: refs/heads/master@{#475538}
4 files changed