Ensure that GVN eliminates all transitions that are dominated by an equivalent transition, even if there is a DependsOn-changing instruction in between.

R=fschneider@chromium.org

Review URL: https://chromiumcodereview.appspot.com/9365057

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@10731 ce2b1a6d-e550-0410-aec6-3dcde31c8c00