This is the first step towards merging the ContentArray into the DescriptorArray, (hence reclaiming 3 words per descriptor array).

Review URL: https://chromiumcodereview.appspot.com/10411067

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@11665 ce2b1a6d-e550-0410-aec6-3dcde31c8c00