remove TorchTNT dependencies

[JKSenthil]

Summary: remove all dependencies to TorchTNT, especially to avoid any recursive dependency issues in OSS

also copied all_gather_tensors from torchtnt into torcheval synclib. This function can be further optimized, since it currently all_gathers to get all tensor sizes, but this is already needed to be done in the synclib as well, so an all_gather can be saved here. Will do in future diff

Differential Revision: D48340818

[facebook-github-bot]

This pull request was exported from Phabricator. Differential Revision: D48340818

[codecov[bot]]

Codecov Report

Merging #173 (c5bf807) into main (798037d) will decrease coverage by 0.07%. The diff coverage is 19.80%.

@@            Coverage Diff             @@
##             main     #173      +/-   ##
==========================================
- Coverage   24.67%   24.61%   -0.07%     
==========================================
  Files         173      173              
  Lines        9921    10016      +95     
==========================================
+ Hits         2448     2465      +17     
- Misses       7473     7551      +78     

Files Changed	Coverage Δ
torcheval/metrics/synclib.py	14.18% <9.75%> (-3.47%)	:arrow_down:
torcheval/metrics/toolkit.py	28.90% <18.18%> (-0.85%)	:arrow_down:
tests/metrics/test_synclib.py	17.98% <28.57%> (+2.89%)	:arrow_up:

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[facebook-github-bot]

This pull request was exported from Phabricator. Differential Revision: D48340818

[facebook-github-bot]

This pull request was exported from Phabricator. Differential Revision: D48340818

[facebook-github-bot]

This pull request was exported from Phabricator. Differential Revision: D48340818

[facebook-github-bot]

This pull request was exported from Phabricator. Differential Revision: D48340818