Sync parser and preparser on do-while and return statements.

Sync parser and preparser on do-while and return statements.

This CL fixes the preparser to have the same liberal automatic semicolon
insertion behaviour as the parser. In the case of a return statement in
global code we throw a syntax error at runtime rather than an early error
due to compatibility with KJS. However that hack allowed the following
syntactically incorrect program in global code in the parser but not in
the preparser:
  if (false) return else {}
while the slightly saner version with the obligatory semicolon
  if (false) return; else {}
was disallowed in the parser, but the preparser allowed it. This CL also
fixes that issue.

BUG=v8:1856
TEST=cctest/test-parsing.cc

Review URL: http://codereview.chromium.org/8844002

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@10201 ce2b1a6d-e550-0410-aec6-3dcde31c8c00