Add monkey patch for Qwen2 models

[chiwanpark]

Summary

This PR adds a monkey patch script for Qwen2 models. I've copied the monkey patch script for Mixtral because the Qwen2 models have the same structure of Mixtral. Also, I've checked the forward method of Qwen2ForCausalLM class (link) to apply the fused linear cross entropy loss.

Testing Done

• run make test to ensure correctness
• run make checkstyle to ensure code style
• run make test-convergence to ensure convergence

❯ make test
pytest --disable-warnings test/ --ignore=test/convergence
================================================ test session starts =================================================
platform linux -- Python 3.10.12, pytest-8.3.2, pluggy-1.5.0
rootdir: /data/ovis_915/bell/Liger-Kernel.git
plugins: anyio-4.4.0
collected 114 items                                                                                                  

test/transformers/test_cross_entropy.py ..........................................................             [ 50%]
test/transformers/test_fused_linear_cross_entropy.py ......                                                    [ 56%]
test/transformers/test_geglu.py ........                                                                       [ 63%]
test/transformers/test_rms_norm.py ................                                                            [ 77%]
test/transformers/test_rope.py ............                                                                    [ 87%]
test/transformers/test_swiglu.py ........                                                                      [ 94%]
test/transformers/test_trainer_integration.py ...                                                              [ 97%]
test/transformers/test_transformers_monkey_patch.py .                                                          [ 98%]
test/triton/test_triton_monkey_patch.py ..                                                                     [100%]

=========================================== 114 passed in 62.15s (0:01:02) ===========================================

❯ make checkstyle 
flake8 .; flake8_status=$?; \
isort .; isort_status=$?; \
black .; black_status=$?; \
if [ $flake8_status -ne 0 ] || [ $isort_status -ne 0 ] || [ $black_status -ne 0 ]; then \
        exit 1; \
fi
Skipped 1 files
All done! ✨ 🍰 ✨
52 files left unchanged.

❯ make test-convergence 
HF_DATASETS_OFFLINE=1 pytest --disable-warnings test/convergence
================================================ test session starts =================================================
platform linux -- Python 3.10.12, pytest-8.3.2, pluggy-1.5.0
rootdir: /data/ovis_915/bell/Liger-Kernel.git
plugins: anyio-4.4.0
collected 8 items                                                                                                    

test/convergence/test_mini_models.py ......                                                                    [ 75%]
test/convergence/test_mini_models_no_logits.py ..                                                              [100%]

================================================= 8 passed in 55.44s =================================================

[ByronHsu]

This shipping speed is crazy!