Fix FlauBERT GPU test
# [Codecov](https://codecov.io/gh/huggingface/transformers/pull/6142?src=pr&el=h1) Report
> Merging [#6142](https://codecov.io/gh/huggingface/transformers/pull/6142?src=pr&el=desc) into [master](https://codecov.io/gh/huggingface/transformers/commit/54f9fbeff822ec0547fd23d0338654456925f6b7&el=desc) will **decrease** coverage by `0.03%`.
> The diff coverage is `100.00%`.

[![Impacted file tree graph](https://codecov.io/gh/huggingface/transformers/pull/6142/graphs/tree.svg?width=650&height=150&src=pr&token=9qOlN6Hb1c)](https://codecov.io/gh/huggingface/transformers/pull/6142?src=pr&el=tree)

```diff
@@            Coverage Diff             @@
##           master    #6142      +/-   ##
==========================================
- Coverage   78.35%   78.32%   -0.04%     
==========================================
  Files         146      146              
  Lines       26403    26403              
==========================================
- Hits        20689    20679      -10     
- Misses       5714     5724      +10     
```


| [Impacted Files](https://codecov.io/gh/huggingface/transformers/pull/6142?src=pr&el=tree) | Coverage Δ | |
|---|---|---|
| [src/transformers/modeling\_flaubert.py](https://codecov.io/gh/huggingface/transformers/pull/6142/diff?src=pr&el=tree#diff-c3JjL3RyYW5zZm9ybWVycy9tb2RlbGluZ19mbGF1YmVydC5weQ==) | `86.61% <100.00%> (ø)` | |
| [src/transformers/generation\_tf\_utils.py](https://codecov.io/gh/huggingface/transformers/pull/6142/diff?src=pr&el=tree#diff-c3JjL3RyYW5zZm9ybWVycy9nZW5lcmF0aW9uX3RmX3V0aWxzLnB5) | `83.95% <0.00%> (-2.26%)` | :arrow_down: |
| [src/transformers/file\_utils.py](https://codecov.io/gh/huggingface/transformers/pull/6142/diff?src=pr&el=tree#diff-c3JjL3RyYW5zZm9ybWVycy9maWxlX3V0aWxzLnB5) | `82.20% <0.00%> (-0.29%)` | :arrow_down: |

------

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