They depend on container dimensions and should not be allowed as initial-value.
rdar://104550943
Pull request: https://github.com/WebKit/WebKit/pull/9035
Submitted web-platform-tests pull request: https://github.com/web-platform-tests/wpt/pull/38141
Committed 259298@main (1dc6982298be): <https://commits.webkit.org/259298@main> Reviewed commits have been landed. Closing PR #9035 and removing active labels.