Fingerprinting: Too Many Open Files

Maybe this is not a standard use case, but if you run `fingerprint_file` for approximately 500 files in a row, you can end up with an OSError.

```
File "/usr/local/lib/python3.10/dist-packages/audioread/__init__.py", line 127, in audio_open
return BackendClass(path)
File "/usr/local/lib/python3.10/dist-packages/audioread/rawread.py", line 59, in __init__
self._fh = open(filename, 'rb')
OSError: [Errno 24] Too many open files: '/home/dlu/Music/PathOfAnMp3ThatMakesMeSeemHipAndCool.mp3'
```

Running on Ubuntu 22.04.

Start by reproducing the failure with fingerprint_file over approximately 500 files on Ubuntu 22.04, then trace how each file is opened through audioread. Done means the same sequential workload no longer raises OSError 24; the payload does not name a repository file or test to run.

Written by the indexing model from the issue text.