Fix issue of wrong number of tokens per GPUs affecting loss normalization in trainer.py#40610

SamuelBarryCS wants to merge 5 commits intohuggingface:mainhuggingface/transformers:mainfrom

SamuelBarryCS:fix-trainer-multi-gpus-loss-normalizationSamuelBarryCS/transformers:fix-trainer-multi-gpus-loss-normalizationCopy head branch name to clipboard