feat(atenlib): add ops(nll_loss)

[xiaowuhu]

No description provided.

[codecov]

Codecov Report

Merging #453 (1558288) into main (7534a16) will increase coverage by 0.09%.
The diff coverage is 97.50%.

@@            Coverage Diff             @@
##             main     #453      +/-   ##
==========================================
+ Coverage   73.60%   73.70%   +0.09%     
==========================================
  Files         109      109              
  Lines       10821    10860      +39     
  Branches     1115     1127      +12     
==========================================
+ Hits         7965     8004      +39     
+ Misses       2551     2550       -1     
- Partials      305      306       +1     

Impacted Files	Coverage Δ
...s/function_libs/torch_aten/ops_correctness_test.py	90.11% <88.88%> (-0.04%)	⬇️
onnxscript/function_libs/torch_aten/ops/nn.py	65.22% <100.00%> (+3.35%)	⬆️

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[justinchuby]

There’s some comments

[justinchuby]

I see what's happening. Let me think about this

[justinchuby]

@shubhambhokare1 I think your PR on optional support will be very useful for this

[justinchuby]

For this op, can we skip when weight is None for now and add a fix me? I will need to spend some time to make the check right.