undefined is passed unchanged as the receiver for strict-mode
functions through call and apply. Also, if a strict-mode function is
called without an explicit receiver, undefined is passed as the
receiver (not the global object as for other functions).

R=vegorov@chromium.org
BUG=89236
TEST=mjsunit/debug-scopes.js

Review URL: http://codereview.chromium.org/7388011

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@8675 ce2b1a6d-e550-0410-aec6-3dcde31c8c00