~0.6% regression on Speedometer 2 on iPhone from dropping uncheckedAppend() in 268700@main.
<rdar://116706935>
Pull request: https://github.com/WebKit/WebKit/pull/20017
Committed 270254@main (9b178a5d519f): <https://commits.webkit.org/270254@main> Reviewed commits have been landed. Closing PR #20017 and removing active labels.