that an element is mirrored in memory) for elements whose target is a
register.  This avoids generating some duplicate merge blocks.

Review URL: http://codereview.chromium.org/40005

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@1403 ce2b1a6d-e550-0410-aec6-3dcde31c8c00