Verifies that:
* There shouldn't be any (IntPtr) or (IntPtr, bool) constructors.
* The (NativeHandle) or (NativeHandle, bool) constructors should not be public.
* The constructors correctly chain to the base constructor according to our usual
pattern: the (IntPtr) ctor must chain to the self/base (IntPtr, bool) constructor
passing 'false' for the owns parameter.
* The constructors don't have any extra code in them (barring a few exceptions).
Rolf Bjarne Kvinge