Pass any verbosity from test/run_test.py to pytest (#48204)
Summary:
Previously it was only possible to pass up to one [verbosity level](https://adamj.eu/tech/2019/10/03/my-most-used-pytest-commandline-flags/) to `pytest` when running a test via `test/run_test.py`. Presumably that behavior was never added because `unittest` [doesn't do anything extra](https://stackoverflow.com/a/1322648/5044950) when given more than one `--verbose` flag. This PR removes that limitation.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/48204
Test Plan:
Make a dummy `pytest`-style file `test/test_foo.py`:
```py
def test_bar():
assert 'hello\n' * 10 == 'hello\n' * 20
```
Then add `'test_foo'` to both `TESTS` and `USE_PYTEST_LIST` in `test/run_test.py`, and run this command:
```sh
test/run_test.py -vvi test_foo
```
Reviewed By: walterddr
Differential Revision: D25069147
Pulled By: samestep
fbshipit-source-id: 2765ee78d18cc84ea0e262520838993f9e9ee04f
