Replace Span implementation with one from libc++, which is more spec complient
Created attachment 431824 [details] Patch
Created attachment 431825 [details] Patch
Created attachment 431826 [details] Patch
Created attachment 431827 [details] Patch
Created attachment 431828 [details] Patch
Committed r279062 (238982@main): <https://commits.webkit.org/238982@main> All reviewed patches have been landed. Closing bug and clearing flags on attachment 431828 [details].
<rdar://problem/79545189>