regression in py38 with bool-as-index deprecation warning

Also reported upstream at https://bugs.python.org/issue37980

With numpy 1.17.1 and python37 the following does not warn

sorted([1, 2], reverse=np.bool_(True))

but with py38

In [2]: sorted([1, 2], reverse=np.bool_(True))                                                                                                                  
<ipython-input-2-6726f33270df>:1: DeprecationWarning: In future, it will be an error for 'np.bool_' scalars to be interpreted as an index
  sorted([1, 2], reverse=np.bool_(True))
Out[2]: [2, 1]

This bisects to python/cpython#11952 which use __index__ in more places which is tripping the deprecation in a surprising place.

sorted([1, 2], reverse=bool(np.bool_(True)))

Works in all cases.