Expose all constructor parameters for BertTokenizerFast
Signed-off-by: Morgan Funtowicz <morgan@huggingface.co>
# [Codecov](https://codecov.io/gh/huggingface/transformers/pull/2921?src=pr&el=h1) Report
> Merging [#2921](https://codecov.io/gh/huggingface/transformers/pull/2921?src=pr&el=desc) into [master](https://codecov.io/gh/huggingface/transformers/commit/d490b5d5003654f104af3abd0556e598335b5650?src=pr&el=desc) will **not change** coverage.
> The diff coverage is `n/a`.

[![Impacted file tree graph](https://codecov.io/gh/huggingface/transformers/pull/2921/graphs/tree.svg?width=650&token=9qOlN6Hb1c&height=150&src=pr)](https://codecov.io/gh/huggingface/transformers/pull/2921?src=pr&el=tree)

```diff
@@           Coverage Diff           @@
##           master    #2921   +/-   ##
=======================================
  Coverage   75.35%   75.35%           
=======================================
  Files          94       94           
  Lines       15444    15444           
=======================================
  Hits        11638    11638           
  Misses       3806     3806
```


| [Impacted Files](https://codecov.io/gh/huggingface/transformers/pull/2921?src=pr&el=tree) | Coverage Δ | |
|---|---|---|
| [src/transformers/tokenization\_bert.py](https://codecov.io/gh/huggingface/transformers/pull/2921/diff?src=pr&el=tree#diff-c3JjL3RyYW5zZm9ybWVycy90b2tlbml6YXRpb25fYmVydC5weQ==) | `96.99% <ø> (ø)` | :arrow_up: |

------

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