Fail gracefully upon tokenizer logging failure (#2035)

[haileyschoelkopf]

closes #2035 .

If adding detailed tokenizer info to logs failed for whatever reason, previously, this would result in the run erroring out before saving results or printing the results table.

This PR causes tokenizer info to simply not be logged when a failure occurs.

[LSinev]

May I suggest using some sort of loop to check and fill dict with tokenization info for such case. Because in #2035 problem is that not all tokens defined in tokenizer, other info may be good. So partial logging may be done.
May be some loop with storage.update for each successfull step.
Or maybe [getattr(lm.tokenizer, "pad_token", None), getattr(lm.tokenizer, "pad_token_id", None)] if supported.

cc @artemorloff as original author of #1731 changes