This relands commit ea74f0f8.

The revert was due to failures in cctest/test-heap/ReleaseOverReservedPages,
caused by apparent changes to memory layout and fragmentation of the
first page. Eliminating a situation in messages.js where this CL has had
an effect on map transitions seems to solve the issue.

R=verwaest@chromium.org

Review URL: https://codereview.chromium.org/714883003

Cr-Commit-Position: refs/heads/master@{#25266}
git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@25266 ce2b1a6d-e550-0410-aec6-3dcde31c8c00