experimental commit

[corochann]

DO NOT MERGE.

this is to check scaler_serialize test.

[corochann]

I understand that issue comes from numpy behavior has changed from version 1.16.3. Now we need to pass allow_pickle=True explicitly in order to load None object.

Reference: https://stackoverflow.com/questions/55824625/how-to-fix-object-arrays-cannot-be-loaded-when-allow-pickle-false-in-the-sketc

This should be fixed in chainer serializer.load_npz.