[BE] f-stringify torch/ and scripts (#105538)

This PR is a follow up on the pyupgrade series to convert more strings to use f-strings using `flynt`.

- https://docs.python.org/3/reference/lexical_analysis.html#f-strings
- https://pypi.org/project/flynt/

Command used:

```
flynt torch/ -ll 120
flynt scripts/ -ll 120
flynt tools/ -ll 120
```

and excluded `collect_env.py`

Pull Request resolved: https://github.com/pytorch/pytorch/pull/105538
Approved by: https://github.com/ezyang, https://github.com/malfet

tools/test/gen_operators_yaml_test.py

@@ -61,9 +61,7 @@ class GenOperatorsYAMLTest(unittest.TestCase):
         filtered_configs = list(filter(filter_func, config))
         assert (
             len(filtered_configs) == 2
-        ), "Expected 2 elements in filtered_configs, but got {}".format(
-            len(filtered_configs)
-        )
+        ), f"Expected 2 elements in filtered_configs, but got {len(filtered_configs)}"
 
     def test_verification_success(self):
         filter_func = make_filter_from_options(