- Do not keep growing the zone segment size exponentially. By putting
  an upper limit on the segment size we limit the requirements for
  contiguous memory allocation.

Review URL: http://codereview.chromium.org/12984

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@926 ce2b1a6d-e550-0410-aec6-3dcde31c8c00