1. Change the AST node type CallNew to be a subclass of Expression
   rather than Call.  It's not really a call but it just happens to
   have the same fields.

2. Change our error reporting for invalid left-hand sides in for-in
   statements, pre- and postfix count expressions, and assignments.
   Before we signaled a syntax error at compile time *unless* the LHS
   was a function call or 'new' expression, in which case we signaled
   a reference error at runtime.  Now we signal a reference error at
   runtime in all cases.  This matches the JSC behavior in Safari 4.

Review URL: http://codereview.chromium.org/249039

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@2994 ce2b1a6d-e550-0410-aec6-3dcde31c8c00