Return undefined instead of hard-crashing.

Bug: chromium:1130213
Change-Id: I7e573f46607fc0e7b91db62d881b4209b919028e
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2456087
Commit-Queue: Toon Verwaest <verwaest@chromium.org>
Reviewed-by: Toon Verwaest <verwaest@chromium.org>
Cr-Commit-Position: refs/heads/master@{#70420}