There are many web-platform-tests that are flaky failures that we need to mark expectations for. The following tests are implicated:

imported/w3c/web-platform-tests/workers/WorkerGlobalScope_ErrorEvent_colno.htm
imported/w3c/web-platform-tests/encoding/streams/realms.window.html
imported/w3c/web-platform-tests/dom/nodes/NodeList-static-length-getter-tampered-2.html 
imported/w3c/web-platform-tests/dom/nodes/NodeList-static-length-getter-tampered-1.html
imported/w3c/web-platform-tests/dom/nodes/NodeList-static-length-getter-tampered-3.html
imported/w3c/web-platform-tests/workers/WorkerGlobalScope_ErrorEvent_filename.htm 
imported/w3c/web-platform-tests/css/css-writing-modes/forms/text-input-vertical-overflow-no-scroll.html
imported/w3c/web-platform-tests/html/browsers/browsing-the-web/navigating-across-documents/javascript-url-return-value-handling-dynamic.html
imported/w3c/web-platform-tests/mediacapture-record/MediaRecorder-peerconnection.https.html
imported/w3c/web-platform-tests/html/cross-origin-opener-policy/reporting/navigation-reporting/reporting-coop-navigated-opener.https.html
imported/w3c/web-platform-tests/webcodecs/videoFrame-serialization.crossAgentCluster.https.html
imported/w3c/web-platform-tests/webrtc/simulcast/getStats.https.html
imported/w3c/web-platform-tests/cookies/path/default.html
imported/w3c/web-platform-tests/css/motion/offset-path-shape-polygon-002.html
imported/w3c/web-platform-tests/css/motion/offset-path-shape-polygon-003.html
imported/w3c/web-platform-tests/css/css-masking/clip-path/animations/clip-path-animation-custom-timing-function.html
imported/w3c/web-platform-tests/css/css-backgrounds/background-size-percentage-root.html
imported/w3c/web-platform-tests/html/canvas/offscreen/manual/the-offscreen-canvas/offscreencanvas.transfer.to.imagebitmap.w.html

This is a master bug for these tests. Once expectations have landed for these I will branch the individual bugs off of this one. However, many of these are very trivially flaky, and appear to have been occurring for a long time. So there may not be much that can be done for them.