Obey the flag --lazy in the toplevel code generator.

Obey the flag --lazy in the toplevel code generator.

There were two separate implementations of the function
'BuildBoilerplate' that is used to compile function declarations and
function literals.  The implementations did not do exactly the same
thing.  In particular, one ignored the flag --lazy.

Combine the two implementations.

Review URL: http://codereview.chromium.org/360011

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@3218 ce2b1a6d-e550-0410-aec6-3dcde31c8c00