Fix Flava FlavaForPreTrainingIntegrationTest test
# What does this PR do?

Fix Flava CI failure
```
>       self.assertAlmostEqual(outputs.loss_info.mmm_text.item(), 1.75533199)
E       AssertionError: 1.7553329467773438 != 1.75533199 within 7 places (9.56777343796844e-07 difference)
```
Just change the argument `places` to `4`.

[Job run log](https://github.com/huggingface/transformers/runs/6416748323?check_suite_focus=true) 
cc @apsdehal for information :-)<|||||>_The documentation is not available anymore as the PR was closed or merged._