These checks are critical even in release mode. They won't impact
runtime performance since this happens at snapshot-time.

TBR=yangguo@chromium.org

Bug: v8:6666
Change-Id: I342d9f80c6b882363da00630385686ac6a02cf5d
Reviewed-on: https://chromium-review.googlesource.com/964524
Commit-Queue: Jakob Gruber <jgruber@chromium.org>
Reviewed-by: Jakob Gruber <jgruber@chromium.org>
Cr-Commit-Position: refs/heads/master@{#51966}