Simplify logic in Node::defaultEventHandler() to address Ryosuke's feedback after 270654@main.
Pull request: https://github.com/WebKit/WebKit/pull/20432
Committed 270680@main (808409e969bb): <https://commits.webkit.org/270680@main> Reviewed commits have been landed. Closing PR #20432 and removing active labels.
<rdar://problem/118359674>