Reapply r8783 with an additional fix.

Because the preparser and parser do not use the same scope analysis to
determine if a function can be lazily compiled, the parser can have false
positives.  Rather than treating this as a parse error, treat the preparser
as authoritative and eagerly compile the function.

R=lrn@chromium.org
BUG=
TEST=

Review URL: http://codereview.chromium.org/7565003

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@8797 ce2b1a6d-e550-0410-aec6-3dcde31c8c00