Otherwise allocated external pointer handles may be swept if never set
by the caller.

Bug: v8:10391
Change-Id: I3d727b80635ac8e21bd403de6bcad59091ed80a0
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3832528Reviewed-by: Samuel Groß <saelo@chromium.org>
Reviewed-by: Jakob Kummerow <jkummerow@chromium.org>
Commit-Queue: Shu-yu Guo <syg@chromium.org>
Cr-Commit-Position: refs/heads/main@{#82597}