This makes sure Runtime_ArrayBufferNeuter fails gracefully on array
buffers that are non-neuterable. Note that this runtime function is
whitelisted on ClusterFuzz and otherwise only used for testing.

R=cbruni@chromium.org
BUG=chromium:743215,v8:6534

Change-Id: I5069e615468f8789bf4fd87bb1e093a18bfd0347
Reviewed-on: https://chromium-review.googlesource.com/574168Reviewed-by: Camillo Bruni <cbruni@chromium.org>
Commit-Queue: Michael Starzinger <mstarzinger@chromium.org>
Cr-Commit-Position: refs/heads/master@{#46710}