CHECK is accessing 1 byte across object boundary because
*expect and *actual will return the object address with
tag. And memcmp should return 0 if we expect (expected == actual)

R=cbruni@chromium.org, gsathya@chromium.org, ishell@chromium.org

Bug: v8:6443, v8:7569
Change-Id: I316e450a80400cea4c9394dbe470932a1f30cea5
Reviewed-on: https://chromium-review.googlesource.com/1142351Reviewed-by: Camillo Bruni <cbruni@chromium.org>
Reviewed-by: Sathya Gunasekaran <gsathya@chromium.org>
Commit-Queue: Junliang Yan <jyan@ca.ibm.com>
Cr-Commit-Position: refs/heads/master@{#54561}