variables rather than in a stack-allocated struct.  The struct field
values turned out not to be available in minidumps.

Review URL: http://codereview.chromium.org/460069


git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@3417 ce2b1a6d-e550-0410-aec6-3dcde31c8c00