llama : improve BERT tokenization (#5740)
* implement nfd for stripping accents in wpm tokenizer
* sort nfd map; reuse iterator
* use builtin tolower
* add locale include
* Simplify to_lower cases
Co-authored-by: Jared Van Bortel <cebtenzzre@gmail.com>
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Co-authored-by: Jared Van Bortel <cebtenzzre@gmail.com>