Chromium builds indicate that moving an optional doesn't reset the
source, and the source still indicates it has a value.
That may be a bug in base::optional, but we should fix it here first to
resolve current crashes.

Bug: chromium:1154636
Cq-Include-Trybots: luci.v8.try:v8_linux_blink_rel
Change-Id: Ibfb53b6d06d5f0310e68b200cc27ca318a5a57e5
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3366235Reviewed-by: Clemens Backes <clemensb@chromium.org>
Reviewed-by: Michael Lippautz <mlippautz@chromium.org>
Commit-Queue: Omer Katz <omerkatz@chromium.org>
Cr-Commit-Position: refs/heads/main@{#78475}