[benchmark tool] trainer-benchmark.py (#14934)
[benchmark tool] trainer-benchmark.py (#14934)

* [benchmark tool] trainer-benchmark.py

* improve

* massive rework/expansion

* fix

* mucho improved

* improved

* fix prefix

* fix

* fix diff calculation

* address suggestions
huggingface/transformers,huggingface/transformers,huggingface/transformers,huggingface/transformers