use newer unittest.mock everwhere

[a-detiste]

this is the same pattern as already seen in test_poincare.py

[mpenkov]

I think even simpler from unittest import mock is safe.

That submodule has been around since Python 3.3. There is no way it won't be available. The existing behavior is a hangover from the days when we supported Python 2.7.

[a-detiste]

gensim/gensim/test/test_parsing.py

Line 34 in 645c2d1

-> I studied this one :-)