Let's add interpolation support for <transform-function> custom properties.
Pull request: https://github.com/WebKit/WebKit/pull/7755
Submitted web-platform-tests pull request: https://github.com/web-platform-tests/wpt/pull/37558
Committed 258009@main (b841cb737eae): <https://commits.webkit.org/258009@main> Reviewed commits have been landed. Closing PR #7755 and removing active labels.
<rdar://problem/103455678>