Made test output iterators have value_type of 'void'; matches ones in library

git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@171980 91177308-0d34-0410-b5e6-96231b3b80d8

test/support/nothing_to_do.pass.cpp

@@ -0,0 +1,13 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is dual licensed under the MIT and the University of Illinois Open
+// Source Licenses. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+int main()
+{
+}