Follow-up to #31108

Folder is wpt/tests/resize-observer.

• calculate-depth-for-node.html requires attachShadow.
• devicepixel.html requires dealing with device pixel calculations(see

  servo/components/script/dom/resizeobserver.rs

  Line 281 in 013473f

  // TODO(#31182): add support for border box, and device pixel size, calculations.

  ).
• eventloop.html fails in relation to Raf delivery.
• /resize-observer/change-layout-in-error.html fails in relation to Raf delivery.
• fragments.html doesn't support more than one fragment
• notify.html need to notify the observer when child node appended and removed. (ResizeObserver depth calculation isn't correct #40111)
• observe.html requires Implement HTMLImageElement decode #31183 making the full suite pass. At least one test(test7?) appears intermittently to timeout, and when it passes it makes other test fails(as opposed to not run). See Fix DOMRect calc in ResizeObserverEntry #32549 for how to make at least three tests pass. Others remain to un-investigated.
• ordering.html requires Implement IntersectionObserver #31021
• scrollbars-2.html calculations are wrong
• scrollbars.html calculations are wrong
• svg-with-css-box-001.html need to observe svg
• svg.html need to observe svg
• iframe-same-origin.html appears intermittent for an unknown reason(I haven't seen it fail locally yet, making it hard to debug so far). See Mark some ResizeObserver tests as flaky #32546