REGRESSION (258521@main): Can end up scrolled to an invalid offset, blank space above page
<rdar://problem/103977580>
Pull request: https://github.com/WebKit/WebKit/pull/8412
Committed 258687@main (6e41546bc076): <https://commits.webkit.org/258687@main> Reviewed commits have been landed. Closing PR #8412 and removing active labels.