AutoTokenizer Encode Error
### System Info

For the LlamaTokenizer, I can get correct encoding result when directly loading from LlamaTokenizer. But the results are incorrect when using AutoTokenizer.  Another issue is loading the AutoTokenizer much slower than directly loading the LlamaTokenizer. It take around 4 mins to load the tokenizer from the path when using AutoTokenizer, while it only takes one second if directly using the LlamaTokenizer. 

### Who can help?

@ArthurZucker

### Information

- [x] The official example scripts
- [ ] My own modified scripts

### Tasks

- [ ] An officially supported task in the `examples` folder (such as GLUE/SQuAD, ...)
- [x] My own task or dataset (give details below)

### Reproduction

Python version: 3.8.16
transformers version: 4.28.1

Follow the given example:

```
from transformers import LlamaTokenizer, AutoTokenizer

model_path = 'openlm-research/open_llama_7b_700bt_preview'
str = ' is embarassed, because Samantha made snide comments about the shirt Rebecca was wearing.'

tokenizer1 = LlamaTokenizer.from_pretrained(model_path)
tokenizer2 = AutoTokenizer.from_pretrained(model_path)

ret1 = tokenizer1.encode(str, add_special_tokens=False)
ret2 = tokenizer2.encode(str, add_special_tokens=False)

print(ret1)
print(ret2)

```


### Expected behavior

ret1: [322, 2661, 285, 14363, 31844, 906, 23982, 985, 3668, 483, 4309, 562, 266, 13803, 15136, 393, 7732, 31843]
ret2: [31822, 322, 2661, 285, 14363, 31844, 906, 23982, 985, 3668, 483, 4309, 562, 266, 13803, 15136, 393, 7732, 31843]

ret1 is the expected output and ret2 is an error result from AutoTokenizer. AutoTokenizer add an additional token, 31822 (which is a space token), to the encoding results.

Hey! You are using an old version of the tokenizer. You should be using the one available [here](https://huggingface.co/huggyllama/llama-7b). This issue was already fixed. 

AutoTokenizer has to convert the slow tokenizer to a fast one, which takes of course a lot of time since the model was not saved on the shared repo. <|||||>This issue has been automatically marked as stale because it has not had recent activity. If you think this still needs to be addressed please comment on this thread.

Please note that issues that do not follow the [contributing guidelines](https://github.com/huggingface/transformers/blob/main/CONTRIBUTING.md) are likely to be ignored.