xref numpyGH-12028

Current behavior:

>>> np.dot(None, None)
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/Users/shoyer/dev/numpy/numpy/core/overrides.py", line 175, in public_api
    implementation, public_api, relevant_args, args, kwargs)
TypeError: unsupported operand type(s) for *: 'NoneType' and 'NoneType'

>>> np.stack([], invalid=True)
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/Users/shoyer/dev/numpy/numpy/core/overrides.py", line 148, in public_api
    relevant_args = dispatcher(*args, **kwargs)
TypeError: _stack_dispatcher() got an unexpected keyword argument 'invalid'

With this change:

>>> np.dot(None, None)
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "<string>", line 6, in dot
TypeError: unsupported operand type(s) for *: 'NoneType' and 'NoneType'

>>> np.stack([], invalid=True)
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "<string>", line 4, in stack
TypeError: _stack_dispatcher() got an unexpected keyword argument 'invalid'