This is necessary even for recursive calls because we're sharing optimized code among closures, which could call each other and have distinct contexts.

BUG=138887
TEST=mjsunit/regress/regress-crbug-138887

Review URL: https://chromiumcodereview.appspot.com/10834031

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@12201 ce2b1a6d-e550-0410-aec6-3dcde31c8c00