[web snapshots] Support elements in objects

Bug: v8:11525
Change-Id: I0580787252ab235222e9b9fb2d677015794207eb
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3506485


Reviewed-by: Camillo Bruni <cbruni@chromium.org>
Commit-Queue: Marja Hölttä <marja@chromium.org>
Cr-Commit-Position: refs/heads/main@{#79441}