[torchlib] Migrate torchvision implementations

[justinchuby]

No description provided.

[codecov]

Codecov Report

❌ Patch coverage is 39.13043% with 14 lines in your changes missing coverage. Please review.
✅ Project coverage is 70.07%. Comparing base (27c7f09) to head (4f5d8c3).
⚠️ Report is 1 commits behind head on main.
✅ All tests successful. No failed tests found.

Files with missing lines	Patch %	Lines
onnxscript/function_libs/torch_lib/ops/vision.py	39.13%	14 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #2569      +/-   ##
==========================================
- Coverage   70.09%   70.07%   -0.02%     
==========================================
  Files         220      222       +2     
  Lines       26086    26204     +118     
  Branches     2575     2581       +6     
==========================================
+ Hits        18285    18363      +78     
- Misses       6904     6941      +37     
- Partials      897      900       +3     

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[Copilot]

Pull Request Overview

This PR migrates torchvision implementations by adding support for roi_align and roi_pool operations to the torch_lib vision module. The changes enable ONNX export compatibility for these computer vision operations commonly used in object detection models.

• Adds torchvision::roi_align implementation with proper coordinate transformation and sampling ratio handling
• Adds torchvision::roi_pool implementation using ONNX MaxRoiPool operator
• Updates existing torchvision::nms operation to be trace-only