Duplicate identifier detection must be an early syntax error in strict code,
so errors in otherwise lazily compiled functions must be caught in the
preparser.

Originally introduced in r8541 and reverted in r8542.
Now really compiles on Windows.

Review URL: http://codereview.chromium.org/7782023

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@9172 ce2b1a6d-e550-0410-aec6-3dcde31c8c00