Port preprocessing and tokenizer tests to use `run_preprocessing_layer_test`

[mattdangerw]

We have been slowly working on factoring out common test routines for our testing code.

The last piece of this work will be to port all keras_nlp/tokenizers/*_test.py and keras_nlp/layers/preprocessing/*_test.py layers to use common test routines.

For each file in keras_nlp/tokenizers/*_test.py and keras_nlp/layers/preprocessing/*_test.py

• [ ] Make the first in the file use TestCase.run_preprocessing_layer_test. For example https://github.com/keras-team/keras-nlp/blob/11bece833200548c181810980ff50546da4d748a/keras_nlp/models/bert/bert_tokenizer_test.py#L22-L35
• [ ] Remove any redundant tests. E.g. tf.data tests, batch and unbatched tests, config and serialization tests.

[mohame54]

Hello @mattdangerw I 'd like to work on this issue ?