Spleeter sometimes gets stuck when processing many files

## Description

Looking at task manager I can see that GPU memory is populated, but no CUDA activity.

Also, `python.exe` is using 6.6 GB of RAM.

## Step to reproduce

Just try to process a large amount of files.

## Output

```
Traceback (most recent call last):
File "c:\Users\Username\anaconda3\envs\spleeter-gpu\lib\multiprocessing\process.py", line 258, in _bootstrap
self.run()
File "c:\Users\Username\anaconda3\envs\spleeter-gpu\lib\multiprocessing\process.py", line 93, in run
self._target(*self._args, **self._kwargs)
File "c:\Users\Username\anaconda3\envs\spleeter-gpu\lib\multiprocessing\pool.py", line 108, in worker
task = get()
File "c:\Users\Username\anaconda3\envs\spleeter-gpu\lib\multiprocessing\queues.py", line 335, in get
res = self._reader.recv_bytes()
File "c:\Users\Username\anaconda3\envs\spleeter-gpu\lib\multiprocessing\connection.py", line 216, in recv_bytes
buf = self._recv_bytes(maxlength)
File "c:\Users\Username\anaconda3\envs\spleeter-gpu\lib\multiprocessing\connection.py", line 318, in _recv_bytes
return self._get_more_data(ov, maxsize)
File "c:\Users\Username\anaconda3\envs\spleeter-gpu\lib\multiprocessing\connection.py", line 340, in _get_more_data
ov, err = _winapi.ReadFile(self._handle, left, overlapped=True)
MemoryError
```

## Environment
| | |
| ----------------- | ------------------------------- |
| OS | Windows |
| Installation type | Conda |
| RAM available | 32GB |
| Hardware spec | i7-8700 / RTX 2080 |