Upstream LayoutTests/html/dialog/*.html to WPT

Convert js-test.js based tests to testHarness based on test.
And upstream to WPT.

Bug: 761790
Change-Id: I97b896cce51fa33a8a17c73fb0ed8242249881ff
Reviewed-on: https://chromium-review.googlesource.com/768430
Reviewed-by: Philip Jägenstedt <foolip@chromium.org>
Commit-Queue: Philip Jägenstedt <foolip@chromium.org>
Cr-Commit-Position: refs/heads/master@{#518911}
12 files changed