Explicitly release allocated memory as Vector doesn't do that in dtor.

Review URL: http://codereview.chromium.org/669164

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@4044 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

src/builtins.cc

@@ -339,6 +339,7 @@ static Object* CallJsBuiltin(const char* name,
                                           n_args,
                                           argv.start(),
                                           &pending_exception);
+  argv.Dispose();
   if (pending_exception) return Failure::Exception();
   return *result;
 }