svg/batik/text/textPosition2.svg is flakey; sometimes the surrounding box loads, and sometimes it does not. It's doing:
<use xmlns="http://www.w3.org/2000/svg" xlink:href="../resources/batikLogo.svg#Batik_Tag_Box" xmlns:xlink="http://www.w3.org/1999/xlink"/>
See also bug 85408.
There is some race condition with respect to when invalidateShadowTree is called versus when SVGUseElement::notifyFinished is called. When the test fails, SVGUseElement::notifyFinished is called after Document::implicitClose and a subsequent invalidateShadowTree bails out early due to renderer() being 0.
It could be that this was caused by the patch for https://bugs.webkit.org/show_bug.cgi?id=81985.
*** This bug has been marked as a duplicate of bug 85408 ***