Add unit test for regression in GVN caused by field type tracking.

BUG=v8:3347
LOG=n
R=svenpanne@chromium.org

Review URL: https://codereview.chromium.org/333273004

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@21858 ce2b1a6d-e550-0410-aec6-3dcde31c8c00