html: copy passed tests from chromium
Updates golang/go#23071
Change-Id: I1fdf3fe8c94efdf3c4bf9c39900468381159a032
Reviewed-on: https://go-review.googlesource.com/131178
Run-TryBot: Kunpei Sakai <namusyaka@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>