Previously, we created a JSObject with a non null prototype for an
internal object which isn't what we want as it casues side effects.

Bug: chromium:872514
Cq-Include-Trybots: luci.v8.try:v8_linux_noi18n_rel_ng
Change-Id: I3318044a03318f3d7099f3ba889450c651cea9e1
Reviewed-on: https://chromium-review.googlesource.com/1171186Reviewed-by: Adam Klein <adamk@chromium.org>
Commit-Queue: Sathya Gunasekaran <gsathya@chromium.org>
Cr-Commit-Position: refs/heads/master@{#55062}