I've noticed a fair number of (so far, to me) unexplainable timeouts on tests which use testharness.js in an SVG (XML) container.

A simple example would be:

https://wpt.fyi/results/svg/path/property/getComputedStyle.svg?label=stable&aligned (no difference with 'label=experimental')
http://w3c-test.org/svg/path/property/getComputedStyle.svg

(There are others like it in the same directory and elsewhere within svg/ though. Haven't tried to find any XHTML tests to see if they are affected too.)

which seems to pass when run using the w3c-test link above, and also pass with the "normal" Blink test runner.

Maybe this would've been better reported in the wpt.fyi GH, but since it seems very Blink/Chromium specific, I figured I should take this route, but ferry how you like.