Test failures on recent versions of React 19

[nickserv]

React pre-warms suspended children as of 19.0.0-rc.1 (facebook/react#31541). This seems to have broken the race condition hack I was relying on for some reason. For now, I'm pinning the last working canary release: 19.0.0-rc-380f5d67-20241113.

[nickserv]

I've published my React test results.