Bug 229564 removed the property, but I left some remainders in StyleRareNonInheritedData
Bug 190788 removed -webkit-margin-collapse
Created attachment 447986 [details] Patch
Created attachment 447987 [details] [fast-cq] Patch
Committed r287448 (245583@main): <https://commits.webkit.org/245583@main> All reviewed patches have been landed. Closing bug and clearing flags on attachment 447987 [details].
<rdar://problem/86923041>