Import wpt@16f18d8135a80e89f2e910ca7548999fa2f7937e

Using wpt-import in Chromium 523890aa.
With Chromium commits locally applied on WPT:
b987e8fd "Implement container-progress() function"
ca785e88 "[bfcache] Report null when iframes' atrributes are null"
3dcaebc9 "[Invokers] Reland: Add HandleInvokeInternal on HTMLDialogElement"



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/+/main/docs/testing/web_platform_tests.md

Directory owners for changes in this CL:
dcheng@chromium.org, jarhar@chromium.org:
  external/wpt/domxpath

NOAUTOREVERT=true
R=rubber-stamper@appspot.gserviceaccount.com

No-Export: true
Validate-Test-Flakiness: skip
Cq-Include-Trybots: luci.chromium.try:linux-blink-rel
Change-Id: Ie7f2f7218dbd4580a62e646e61fce09254ac3245
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/5408518
Bot-Commit: Rubber Stamper <rubber-stamper@appspot.gserviceaccount.com>
Commit-Queue: Rubber Stamper <rubber-stamper@appspot.gserviceaccount.com>
Auto-Submit: WPT Autoroller <wpt-autoroller@chops-service-accounts.iam.gserviceaccount.com>
Cr-Commit-Position: refs/heads/main@{#1280530}