tests: add regression test for logger NameError in torchao_quantizer

[dhruvildarji]

Summary

Closes #13104

Issue #13104 reports a NameError: name 'logger' is not defined that occurs at import time when _update_torch_safe_globals() in torchao_quantizer.py raises an ImportError (e.g. when torchao.dtypes.uintx.uint4_layout is missing in newer torchao versions). The exception handler on line 103 calls logger.warning(...), but logger was defined after the function body, so Python raises a NameError instead of the intended warning.

The root fix (moving logger = logging.get_logger(__name__) to line 39, before _update_torch_safe_globals) was already included in PR #12901. This PR adds a regression test to prevent the issue from recurring.

Changes

• Added TorchAoQuantizerModuleTest.test_logger_defined_before_module_level_code in tests/quantization/torchao/test_torchao.py
• The test uses ast to parse the source of torchao_quantizer.py and asserts that the logger assignment appears at an earlier line number than the _update_torch_safe_globals function definition, ensuring the logger is always available when the exception handler runs.
• Does not require GPU or torchao to be installed.

Test plan

• python -m pytest tests/quantization/torchao/test_torchao.py::TorchAoQuantizerModuleTest::test_logger_defined_before_module_level_code -v passes