[Python][C++] scanner(fragment_readahead=0).to_table() hangs indefinitely.

### Describe the bug, including details regarding any error messages, version, and platform.

I've encountered a situation where calling .to_table() on a pyarrow.dataset.Scanner causes the process to hang indefinitely.

```
import pyarrow as pa
import pyarrow.dataset as pd
import pyarrow.parquet as pq
t = pa.table({"col": 'pyarrow'})
pq.write_table(t, 'table.parquet')
pd.dataset('table.parquet').scanner(fragment_readahead=0).to_table()
# never returns
```

Note, that the data to read is minimal and the following works:

```
import pyarrow as pa
import pyarrow.dataset as pd
import pyarrow.parquet as pq
t = pa.table({"col": 'pyarrow'})
pq.write_table(t, 'table.parquet')
pd.dataset('table.parquet').scanner(fragment_readahead=0).head(100)
pyarrow.Table
col: string
----
col: [["p","y","a","r","r","o","w"]]
```

### Version(s): tested on `21.0.0` and `22.0.0` both are affected.

### Component(s)

Python