Manually importing WPT tests.

This recovers the auto-import from crrev.com/c/2712438 and rolls back the webdriver
bidi changes, due to crbug.com/1180409. It also adjusts expectations and baselines
for two flaky tests.

Import wpt@f70aca56a3e5be65fd4d67ee64ca5dbb3ee9413b

Using wpt-import in Chromium d163fd7c6905e456501aba914a24c20b62b4c6dc.
With Chromium commits locally applied on WPT:
5d9c072f2e "Set resource requests' parameters for module service workers scripts."


Note to sheriffs: This CL imports external tests and adds
expectations for those tests; if this CL is large and causes
a few new failures, please fix the failures by adding new
lines to TestExpectations rather than reverting. See:
https://chromium.googlesource.com/chromium/src/+/master/docs/testing/web_platform_tests.md

Directory owners for changes in this CL:
nzolghadr@chromium.org, mustaq@chromium.org:
  external/wpt/pointerevents

NOAUTOREVERT=true

No-Export: true
Cq-Include-Trybots: luci.chromium.try:linux-wpt-identity-fyi-rel,linux-wpt-input-fyi-rel
Change-Id: I95eeee01b64e90dbc9f48f4edd353d66733e48d1
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2713469
Reviewed-by: Stephen McGruer <smcgruer@chromium.org>
Commit-Queue: Luke Z <lpz@chromium.org>
Cr-Commit-Position: refs/heads/master@{#856697}