android: Mock parseInetAddress() method to fix unit tests

android: Mock parseInetAddress() method to fix unit tests

The native parseInetAddressBytes() method called by that method is not
available when running the tests.

Not very pretty and there are some warnings because PowerMock does
reflection in some illegal way but it fixes the unit tests and does
not require any new dependencies like Apache Commons or Guava just to
parse IP addresses without DNS lookup.

Fixes: 2ef473be1532 ("android: Use helper to parse IP addresses where appropriate")
Fixes #3443.