While change crrev.com/c/718338 was changing NULL to nullptr, change
crrev.com/c/711334 was adding another NULL. I noticed this (eventually)
because I was simultaneously trying to write a change which was very
dependent on the precise value being used for null pointers.

BUG=v8:6928,v8:6921

Change-Id: Ib42cccf90c91c050032cc9e34e44c99fd14ff1bb
Reviewed-on: https://chromium-review.googlesource.com/722619
Commit-Queue: Mathias Bynens <mathias@chromium.org>
Reviewed-by: Adam Klein <adamk@chromium.org>
Reviewed-by: Mathias Bynens <mathias@chromium.org>
Cr-Commit-Position: refs/heads/master@{#48651}