Cache: init empty cache when `use_cache` (#34274)
* fix
* fix tests
* fix copies
* add docs
* Revert "add docs"
This reverts commit 32d35634f12ba02781d2ebdee0c8dcfbe992a7b9.
* qwen move deltas
* mllama can potentiall fullgraph compile
* enable mllama compile and fix tests
* remove mllama fixes
