Comparison with merging LLaMA-2 CLM and LLaMA-2

[leegao]

Within https://github.com/fanqiwan/FuseLLM/blob/main/assets/fig_4.png, it would be nice to be able to see a comparison of LLaMA-2, LLaMA-2 CLM, FuseLLM, and a merge using just LLaMA-2, LLaMA-2 CLM as well