- Converts the last builtin, Add to Torque.

Bug: v8:9891
Change-Id: Iefa16b0d4c586ff91b54ead13fa9846064e6eda8
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2204155
Commit-Queue: Bill Budge <bbudge@chromium.org>
Reviewed-by: Jakob Gruber <jgruber@chromium.org>
Reviewed-by: Tobias Tebbi <tebbi@chromium.org>
Cr-Commit-Position: refs/heads/master@{#68026}