Create a sentinel file for each dynamo test failure (#120355)
Created via
```
import os
current_dir = os.path.dirname(os.path.abspath(__file__))
directory = os.path.join(current_dir, 'dynamo_expected_failures')
for name in dynamo_expected_failures:
path = os.path.join(directory, name)
with open(path, 'w') as fp:
pass
```
Differential Revision: [D54036062](https://our.internmc.facebook.com/intern/diff/D54036062)
Pull Request resolved: https://github.com/pytorch/pytorch/pull/120355
Approved by: https://github.com/aorenste, https://github.com/yanboliang
