been made of the element.  Set it when copying an element, clear it
when writing to an element marked copied and discovering that it is
not copied.

The copied flags on entry frames are exact.  Preparing a frame for
merging set the copied flags to be exact (to increase the likelihood
of matching the entry frame or another frame).
Review URL: http://codereview.chromium.org/50005

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@1546 ce2b1a6d-e550-0410-aec6-3dcde31c8c00