title: pypy import clr fails on Windows
body: <p>I tried pythonnet with <code>pypy</code> on Win10. It builds fine, but then fails to <code>import clr</code>. The crash happens after this call in the screenshot.</p>
  
  <p>Any tips/tools for debugging this?</p>
  
  <p><a href="https://i.stack.imgur.com/G6FDt.png" rel="noreferrer"><img src="https://i.stack.imgur.com/G6FDt.png" alt="enter image description here"></a></p>
  
  <pre><code>pypy
  Python 2.7.12 (aff251e54385, Nov 09 2016, 17:54:55)
  [PyPy 5.6.0 with MSC v.1500 32 bit] on win32
  Type "help", "copyright", "credits" or "license" for more information.
  &gt;&gt;&gt;&gt; import clr
  Attempting to load 'Python.Runtime' using standard binding rules.
  'Python.Runtime' not found using standard binding rules.
  Attempting to load Python.Runtime from: 'C:\Python\pypy2-v5.6.0-win32\site-packages\Python.Runtime.dll'.
  Success loading 'Python.Runtime' from: 'C:\Python\pypy2-v5.6.0-win32\site-packages\Python.Runtime.dll'.
  RPython traceback:
    File "pypy_module_cpyext_2.c", line 26114, in type_realize
    File "pypy_module_cpyext_2.c", line 31744, in _type_realize
  Fatal RPython error: AssertionError
  
  This application has requested the Runtime to terminate it in an unusual way.
  Please contact the application's support team for more information.
  </code></pre>
  
  <p><a href="https://github.com/pythonnet/pythonnet/issues/330" rel="noreferrer">Here is the detailed thread about the issue</a></p>