Resync dom web-platform tests from upstream.
Created attachment 400402 [details] Patch
Created attachment 400413 [details] Patch
Created attachment 400421 [details] Patch
Created attachment 400427 [details] Patch
Created attachment 400462 [details] Patch
Created attachment 400465 [details] Patch
Created attachment 400471 [details] Patch
Created attachment 400492 [details] Patch
Committed r262254: <https://trac.webkit.org/changeset/262254> All reviewed patches have been landed. Closing bug and clearing flags on attachment 400492 [details].
<rdar://problem/63729707>