Also removes the JS constructor.

R=jgruber@chromium.org

Bug: v8:7624
Change-Id: I33493ab2fafb35f95fb1822d46d3f249568c0a56
Reviewed-on: https://chromium-review.googlesource.com/999534
Commit-Queue: Jakob Gruber <jgruber@chromium.org>
Reviewed-by: Jakob Gruber <jgruber@chromium.org>
Cr-Commit-Position: refs/heads/master@{#52469}