Implement tofile on tensors to reduce data write time by 40%

[justinchuby]

TODO: tests

This PR introduces the tofile method on tensors (similarly named as the one on numpy arrays), which allows for faster write and lower memory usage on external data by bypassing tobytes().

Compatibility with existing TensorProtocols is maintained in the external data module by using tofile only when it is available in the class. The TorchTensor class in PyTorch exporter should be updated accordingly to leverage the new logic when saving.

Note that io time to disk is reduced by 40% below.

Reference: https://github.com/microsoft/onnxscript/pull/2241/files/b2381658492510a9bcc8c0a8574db7368e33bceb

Before:

________________________________________________________
Executed in   48.08 secs    fish           external
   usr time   60.54 secs    0.00 millis   60.54 secs
   sys time   23.06 secs    1.22 millis   23.06 secs

After:

________________________________________________________
Executed in   45.69 secs    fish           external
   usr time   60.68 secs  244.00 micros   60.68 secs
   sys time   22.22 secs  518.00 micros   22.22 secs

Fix #207

[codecov]

Codecov Report

❌ Patch coverage is 55.10204% with 22 lines in your changes missing coverage. Please review.
✅ Project coverage is 76.57%. Comparing base (feb51e5) to head (40cb60d).
✅ All tests successful. No failed tests found.

Files with missing lines	Patch %	Lines
src/onnx_ir/_core.py	48.57%	14 Missing and 4 partials ⚠️
src/onnx_ir/external_data.py	66.66%	1 Missing and 1 partial ⚠️
src/onnx_ir/tensor_adapters.py	75.00%	2 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #210      +/-   ##
==========================================
- Coverage   76.83%   76.57%   -0.27%     
==========================================
  Files          40       40              
  Lines        4922     4965      +43     
  Branches      980      989       +9     
==========================================
+ Hits         3782     3802      +20     
- Misses        856      873      +17     
- Partials      284      290       +6     

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[justinchuby]

cc @iksnagreb

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud

[justinchuby]

Rename variable to be more accurate. This should be a list of some py objects.