Segmentation fault when loading datasets from file
## Describe the bug
Custom dataset loading sometimes segfaults and kills the process if chunks contain a variety of features/

## Steps to reproduce the bug

Download an example file:
```
wget https://gist.githubusercontent.com/TevenLeScao/11e2184394b3fa47d693de2550942c6b/raw/4232704d08fbfcaf93e5b51def9e5051507651ad/tiny_kelm.jsonl
```
Then in Python:
```
import datasets
tiny_kelm = datasets.load_dataset("json", data_files="tiny_kelm.jsonl", chunksize=100000)
```

## Expected results
a `tiny_kelm` functional dataset

## Actual results
☠️ `Segmentation fault (core dumped)` ☠️

## Environment info
- `datasets` version: 1.14.0
- Platform: Linux-5.11.0-38-generic-x86_64-with-glibc2.29
- Python version: 3.8.10
- PyArrow version: 5.0.0