[torchlib] Mark atan2 as trace_only and map NaN to 0

[justinchuby]

Fix pytorch/pytorch#162570

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 70.38%. Comparing base (710d597) to head (37e7b39).
⚠️ Report is 1 commits behind head on main.
✅ All tests successful. No failed tests found.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #2557      +/-   ##
==========================================
+ Coverage   70.34%   70.38%   +0.03%     
==========================================
  Files         222      222              
  Lines       26616    26619       +3     
  Branches     2661     2661              
==========================================
+ Hits        18724    18736      +12     
+ Misses       6978     6969       -9     
  Partials      914      914              

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