Spec Text:
https://tc39.es/proposal-temporal/#sec-temporal.plaintime.prototype.round

Bug: v8:11544
Change-Id: I564cec6fdc030e3d39a9798c047534228f670dc6
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3692428
Commit-Queue: Frank Tang <ftang@chromium.org>
Reviewed-by: Adam Klein <adamk@chromium.org>
Cr-Commit-Position: refs/heads/main@{#81427}