[Testcase Refactoring] Add hw_classification in test/fx/test_cse_pass.py (#192034)

## Summary
Add hw_classification = HardwareClassification.GENERIC attribute to TestCSEPass class, enabling hardware-based test classification and filtering.

## Changes
test/fx/test_cse_pass.py : import HardwareClassification and add hw_classification to TestCSEPass class。

## Motivation
These tests are hardware-agnostic and should be classified as GENERIC so they can be properly selected and filtered when running on different hardware backends.

## Test Plan
CI: python -m pytest -q test/fx/test_cse_pass.py

## Notes
This is part of the test case refactoring initiative tracked in https://github.com/pytorch/pytorch/issues/185590.

Pull Request resolved: https://github.com/pytorch/pytorch/pull/192034
Approved by: https://github.com/FuDdd, https://github.com/fffrog, https://github.com/albanD