b5200

llama-bench : Add `--override-tensors` arg (#12922)

* Add --override-tensors option to llama-bench

* Correct llama-bench --override-tensors to --override-tensor

* llama-bench: Update --override-tensors parsing to match --tensor-split, appear in test matrix.

* Make new llama-bench util functions static to fix Ubuntu CI

* llama-bench: Correct -ot corner cases (No -ot calls, leading and trailing empty -ot spans, etc.)