It's used when setting up the context snapshot for blink, so we want to
be sure that it doesn't execute script.

Bug: chromium:728583
Change-Id: I46507e18d178e6473dd10348a9f253016a9178b7
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2807615Reviewed-by: Camillo Bruni <cbruni@chromium.org>
Commit-Queue: Jochen Eisinger <jochen@chromium.org>
Cr-Commit-Position: refs/heads/master@{#73920}