Improve bert-japanese tokenizer handling (#8659)
* Make ci fail
* Try to make tests actually run?
* CI finally failing?
* Fix CI
* Revert "Fix CI"
This reverts commit ca7923be7334d4e571b023478ebdd6b33dfd0ebb.
* Ooops wrong one
* one more try
* Ok ok let's move this elsewhere
* Alternative to globals() (#8667)
* Alternative to globals()
* Error is raised later so return None
* Sentencepiece not installed make some tokenizers None
* Apply Lysandre wisdom
* Slightly clearer comment?
cc @sgugger
Co-authored-by: Sylvain Gugger <35901082+sgugger@users.noreply.github.com>
