[WIP]Test Custom Loss Module

[NihalHarish]

Description of changes:

• If the customer over-writes the forward pass function of a Loss module then ZCC has no effect.

Note: The first commit only reproduces the error and does not attempt to fix it.

Style and formatting:

I have run pre-commit install to ensure that auto-formatting happens with every commit.

Issue number, if available

By submitting this pull request, I confirm that you can use, modify, copy, and redistribute this contribution, under the terms of your choice.

[codecov-io]

Codecov Report

Merging #388 into master will increase coverage by 1.41%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##           master     #388      +/-   ##
==========================================
+ Coverage   85.49%   86.91%   +1.41%     
==========================================
  Files          86       86              
  Lines        6514     6517       +3     
==========================================
+ Hits         5569     5664      +95     
+ Misses        945      853      -92     

Impacted Files	Coverage Δ
smdebug/pytorch/hook.py	83.59% <100.00%> (+1.19%)	⬆️
smdebug/core/hook.py	93.88% <0.00%> (+0.39%)	⬆️
smdebug/core/save_config.py	88.80% <0.00%> (+0.79%)	⬆️
smdebug/core/tfevent/event_file_writer.py	97.50% <0.00%> (+1.25%)	⬆️
smdebug/core/access_layer/s3handler.py	69.53% <0.00%> (+1.32%)	⬆️
smdebug/core/utils.py	84.97% <0.00%> (+1.40%)	⬆️
smdebug/core/tfevent/events_writer.py	95.45% <0.00%> (+2.27%)	⬆️
smdebug/core/tfevent/index_file_writer.py	96.87% <0.00%> (+3.12%)	⬆️
smdebug/mxnet/collection.py	80.00% <0.00%> (+3.33%)	⬆️
... and 11 more

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