Many X64 bugs have been due to the difference between (unaligned) Array::kHeaderSize and (aligned) FixedArray::kHeaderSize.
Review URL: http://codereview.chromium.org/155687

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@2502 ce2b1a6d-e550-0410-aec6-3dcde31c8c00