glue datasets returning -1 for test split
### Describe the bug

Downloading any dataset from GLUE has -1 as class labels for test split. Train and validation have regular 0/1 class labels.  This is also present in the dataset card online. 

### Steps to reproduce the bug

```
dataset = load_dataset("glue", "sst2")
for d in dataset:
    # prints out -1
    print(d["label"]
```

### Expected behavior

Expected behavior should be 0/1 instead of -1. 

### Environment info

- `datasets` version: 2.4.0
- Platform: Linux-5.15.0-46-generic-x86_64-with-glibc2.17
- Python version: 3.8.16
- PyArrow version: 8.0.0
- Pandas version: 1.5.3

