... instead of returning undefined.

Bug: chromium:1065094
Change-Id: I0b0397a8affd44b58e7f4777f32ba22bbd001ab1
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2124837Reviewed-by: Toon Verwaest <verwaest@chromium.org>
Commit-Queue: Georg Neis <neis@chromium.org>
Cr-Commit-Position: refs/heads/master@{#66902}