[Benchmark] fix print in benchmark
Tiny change pretty print results.
# [Codecov](https://codecov.io/gh/huggingface/transformers/pull/5242?src=pr&el=h1) Report
> Merging [#5242](https://codecov.io/gh/huggingface/transformers/pull/5242?src=pr&el=desc) into [master](https://codecov.io/gh/huggingface/transformers/commit/9fe09cec76efa1e221c3fd6eb8520ba0a911f092&el=desc) will **decrease** coverage by `0.02%`.
> The diff coverage is `n/a`.

[![Impacted file tree graph](https://codecov.io/gh/huggingface/transformers/pull/5242/graphs/tree.svg?width=650&height=150&src=pr&token=9qOlN6Hb1c)](https://codecov.io/gh/huggingface/transformers/pull/5242?src=pr&el=tree)

```diff
@@            Coverage Diff             @@
##           master    #5242      +/-   ##
==========================================
- Coverage   77.93%   77.91%   -0.03%     
==========================================
  Files         138      138              
  Lines       23860    23860              
==========================================
- Hits        18595    18590       -5     
- Misses       5265     5270       +5     
```


| [Impacted Files](https://codecov.io/gh/huggingface/transformers/pull/5242?src=pr&el=tree) | Coverage Δ | |
|---|---|---|
| [src/transformers/benchmark/benchmark\_utils.py](https://codecov.io/gh/huggingface/transformers/pull/5242/diff?src=pr&el=tree#diff-c3JjL3RyYW5zZm9ybWVycy9iZW5jaG1hcmsvYmVuY2htYXJrX3V0aWxzLnB5) | `69.84% <ø> (ø)` | |
| [src/transformers/trainer.py](https://codecov.io/gh/huggingface/transformers/pull/5242/diff?src=pr&el=tree#diff-c3JjL3RyYW5zZm9ybWVycy90cmFpbmVyLnB5) | `38.44% <0.00%> (-1.18%)` | :arrow_down: |
| [src/transformers/modeling\_tf\_utils.py](https://codecov.io/gh/huggingface/transformers/pull/5242/diff?src=pr&el=tree#diff-c3JjL3RyYW5zZm9ybWVycy9tb2RlbGluZ190Zl91dGlscy5weQ==) | `86.00% <0.00%> (-0.15%)` | :arrow_down: |
| [src/transformers/modeling\_utils.py](https://codecov.io/gh/huggingface/transformers/pull/5242/diff?src=pr&el=tree#diff-c3JjL3RyYW5zZm9ybWVycy9tb2RlbGluZ191dGlscy5weQ==) | `91.26% <0.00%> (+0.12%)` | :arrow_up: |

------

[Continue to review full report at Codecov](https://codecov.io/gh/huggingface/transformers/pull/5242?src=pr&el=continue).
> **Legend** - [Click here to learn more](https://docs.codecov.io/docs/codecov-delta)
> `Δ = absolute <relative> (impact)`, `ø = not affected`, `? = missing data`
> Powered by [Codecov](https://codecov.io/gh/huggingface/transformers/pull/5242?src=pr&el=footer). Last update [9fe09ce...911baec](https://codecov.io/gh/huggingface/transformers/pull/5242?src=pr&el=lastupdated). Read the [comment docs](https://docs.codecov.io/docs/pull-request-comments).
