Add comprehensive minifier tests (#88022)
Adds tests for https://github.com/pytorch/torchdynamo/issues/1241.
To run: `pytest test/dynamo/test_minifier.py`.
Actually runs minifier launcher script and repro scripts, rather than just checking for existence of the minifier launcher script.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/88022
Approved by: https://github.com/mlazos, https://github.com/anijain2305
