V8_INT64_C will be cleaned up in a follow-up CL.

R=tebbi@chromium.org,mlippautz@chromium.org

Bug: v8:7109
Change-Id: I6af97e7266039eb443896b404b77b8e2b5de5adb
Reviewed-on: https://chromium-review.googlesource.com/803294Reviewed-by: Michael Lippautz <mlippautz@chromium.org>
Reviewed-by: Tobias Tebbi <tebbi@chromium.org>
Commit-Queue: Clemens Hammacher <clemensh@chromium.org>
Cr-Commit-Position: refs/heads/master@{#49790}