deps: back-port b049d1a from V8 upstream
Original commit message:
Ensure we align zone memory at 8 byte boundaries on all platforms
BUG=v8:5668
R=verwaest@chromium.org
Review-Url: https://codereview.chromium.org/2672203002
CI: https://ci.nodejs.org/job/node-test-pull-request/6245/ V8 CI: https://ci.nodejs.org/job/node-test-commit-v8-linux/557/