Include the required standard headers used in archives unit test

These files are currently implicitly included from other headers, but we
shouldn't rely on this and include them explicitly as we use std::map<>
and std::auto_ptr<> in this header.

No real changes.

tests/archive/archivetest.h

@@ -14,6 +14,8 @@
 #include "wx/archive.h"
 #include "wx/wfstream.h"
 
+#include <map>
+#include <memory>
 
 ///////////////////////////////////////////////////////////////////////////////
 // Bit flags for options for the tests