Disable optimization for functions that have scopes that cannot be reconstructed from the context chain.

BUG=v8:2071
TEST=mjsunit/regress/regress-2071.js

Review URL: https://chromiumcodereview.appspot.com/10388164

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@11592 ce2b1a6d-e550-0410-aec6-3dcde31c8c00