Automatic update from web-platform-tests Improve left/right arrow handling for menulists that don't have adjacent ones. A menulist invoked by a button, or a menulist invoked by a menuitem in a menubar that only has one menuitem, need to have different keyboard behavior for right/left arrow keys than menulists in a menubar with multiple menuitems. This implements that behavior so that right/left arrows don't unexpectedly close the menu when there's nothing else to move to. In order for the revised tests (using Escape) to pass, this also changes how the previously-focused-element for the popover is set when submenus are opened with a click. Bug: 406566432 Change-Id: Ib36c1b319e60264c6119e48b010606f8681615aa Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/8070218 Commit-Queue: David Baron <dbaron@chromium.org> Reviewed-by: Joey Arhar <jarhar@chromium.org> Cr-Commit-Position: refs/heads/main@{#1660630} -- wpt-commits: a19af30338751ef5bd7412a987e187d2faaa8ca6 wpt-pr: 61222