test: make make-unreadable Python 3 friendly

Make `make-unreadable` python 3 compatible.  `POINTER` is now in
`ctypes` rather than in `ctypes.wintypes`.  Use the new location which
is compatible across python 2 and python 3.

Author: compnerd

test/ModuleInterface/Inputs/make-unreadable.py

@@ -7,7 +7,7 @@
     import ctypes
     AdvAPI32 = ctypes.windll.Advapi32
 
-    from ctypes.wintypes import POINTER
+    from ctypes import POINTER
 
     UNLEN = 256