Stop using Vector::uncheckedAppend() in ISO8601.cpp. Vector::uncheckedAppend() has recently become an alias to Vector::append(), which does bounds checking. Use a more efficient Vector constructor instead.
Pull request: https://github.com/WebKit/WebKit/pull/18477
Committed 268731@main (cc80dcc17dc5): <https://commits.webkit.org/268731@main> Reviewed commits have been landed. Closing PR #18477 and removing active labels.
<rdar://problem/116347642>