It avoids having dead pointers in code from the time it was marked for deoptimization until it is deoptimized.

BUG=320532,v8:2996
TEST=mjsunit/regress/regress-320532.js
LOG=Y
R=danno@chromium.org

Review URL: https://chromiumcodereview.appspot.com/61213012

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@18013 ce2b1a6d-e550-0410-aec6-3dcde31c8c00