Fix on "cache position" for assisted generation (#30068)
* clean commit history I hope
* get kv seq length correctly
* PR suggestions
* Update src/transformers/testing_utils.py
Co-authored-by: Joao Gante <joaofranciscocardosogante@gmail.com>
* add comment
* give gpt bigcode it's own overriden method
* remove code
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Co-authored-by: Joao Gante <joaofranciscocardosogante@gmail.com>
