Revert "Improve inobject field tracking during GVN."

This reverts commit r19427 for breaking the build. Will reland with
fix.

TBR=mstarzinger@chromium.org

Review URL: https://codereview.chromium.org/143203005

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@19248 ce2b1a6d-e550-0410-aec6-3dcde31c8c00