[Misc] Add SPDX-License-Identifier headers to python source files (#12628)

- **Add SPDX license headers to python source files**
- **Check for SPDX headers using pre-commit**

commit 9d7ef44c3cfb72ca4c32e1c677d99259d10d4745
Author: Russell Bryant <rbryant@redhat.com>
Date:   Fri Jan 31 14:18:24 2025 -0500

    Add SPDX license headers to python source files
    
This commit adds SPDX license headers to python source files as
recommended to
the project by the Linux Foundation. These headers provide a concise way
that is
both human and machine readable for communicating license information
for each
source file. It helps avoid any ambiguity about the license of the code
and can
    also be easily used by tools to help manage license compliance.
    
The Linux Foundation runs license scans against the codebase to help
ensure
    we are in compliance with the licenses of the code we use, including
dependencies. Having these headers in place helps that tool do its job.
    
    More information can be found on the SPDX site:
    
    - https://spdx.dev/learn/handling-license-info/

Signed-off-by: Russell Bryant <rbryant@redhat.com>

commit 5a1cf1cb3b80759131c73f6a9dddebccac039dea
Author: Russell Bryant <rbryant@redhat.com>
Date:   Fri Jan 31 14:36:32 2025 -0500

    Check for SPDX headers using pre-commit
Signed-off-by: Russell Bryant <rbryant@redhat.com>

---------
Signed-off-by: Russell Bryant <rbryant@redhat.com>

tests/plugins/vllm_add_dummy_platform/vllm_add_dummy_platform/dummy_platform.py

+# SPDX-License-Identifier: Apache-2.0
+
 from vllm.platforms.cuda import CudaPlatform
 
 

tests/plugins_tests/test_platform_plugins.py

+# SPDX-License-Identifier: Apache-2.0
+
 import torch
 
 from tests.kernels.utils import override_backend_env_variable

tests/prefix_caching/test_disable_sliding_window.py

+# SPDX-License-Identifier: Apache-2.0
 """Compare the with and without prefix caching.
 
 Run `pytest tests/prefix_caching/test_prefix_caching.py`.

tests/prefix_caching/test_prefix_caching.py

+# SPDX-License-Identifier: Apache-2.0
 """Compare the with and without prefix caching.
 
 Run `pytest tests/prefix_caching/test_prefix_caching.py`.

tests/prompt_adapter/test_bloom.py

+# SPDX-License-Identifier: Apache-2.0
+
 import pytest
 
 import vllm

tests/prompt_adapter/test_multi_adapter_inference.py

+# SPDX-License-Identifier: Apache-2.0
+
 from vllm import EngineArgs, LLMEngine, SamplingParams
 from vllm.prompt_adapter.request import PromptAdapterRequest
 

tests/prompt_adapter/test_pa_lora.py

+# SPDX-License-Identifier: Apache-2.0
+
 from huggingface_hub import snapshot_download
 
 from vllm import EngineArgs, LLMEngine, SamplingParams

tests/quantization/test_bitsandbytes.py

+# SPDX-License-Identifier: Apache-2.0
 '''Tests whether bitsandbytes computation is enabled correctly.
 
 Run `pytest tests/quantization/test_bitsandbytes.py`.

tests/quantization/test_compressed_tensors.py

+# SPDX-License-Identifier: Apache-2.0
 """Test model set-up and weight loading for llmcompressor-quantized models.
 
 Run `pytest tests/quantization/test_compressed_tensors.py`.

tests/quantization/test_configs.py

+# SPDX-License-Identifier: Apache-2.0
 """Tests whether Marlin models can be loaded from the autogptq config.
 
 Run `pytest tests/quantization/test_configs.py --forked`.

tests/quantization/test_cpu_offload.py

+# SPDX-License-Identifier: Apache-2.0
+
 # Expanded quantized model tests for CPU offloading
 # Base tests: tests/basic_correctness/test_cpu_offload.py
 

tests/quantization/test_experts_int8.py

+# SPDX-License-Identifier: Apache-2.0
+
 # flake8: noqa
 """Tests experts_int8 quantization startup and generation, 
 doesn't test correctness

tests/quantization/test_fp8.py

+# SPDX-License-Identifier: Apache-2.0
 """Tests whether FP8 computation is enabled correctly.
 
 Run `pytest tests/quantization/test_fp8.py --forked`.

tests/quantization/test_ipex_quant.py

+# SPDX-License-Identifier: Apache-2.0
 """Test model set-up and inference for quantized HF models supported
  on the CPU/GPU backend using IPEX (including AWQ/GPTQ).
  

tests/quantization/test_lm_head.py

+# SPDX-License-Identifier: Apache-2.0
 """Tests whether gptq models with quantized lm_head can be loaded.
 
 Run `pytest tests/quantization/test_quant_lm_head_true.py --forked`.

tests/quantization/test_quark.py

+# SPDX-License-Identifier: Apache-2.0
 """Test model set-up and weight loading for quark-quantized models.
 
 Run `pytest tests/quantization/test_quark.py`.

tests/quantization/test_register_quantization_config.py

+# SPDX-License-Identifier: Apache-2.0
 """Tests register custom quantization config.
 
 See https://github.com/vllm-project/vllm/issues/11926 for more details.

tests/quantization/utils.py

+# SPDX-License-Identifier: Apache-2.0
+
 from vllm.model_executor.layers.quantization import get_quantization_config
 from vllm.platforms import current_platform
 

tests/runai_model_streamer/test_runai_model_streamer_loader.py

+# SPDX-License-Identifier: Apache-2.0
+
 from vllm import SamplingParams
 from vllm.config import LoadConfig, LoadFormat
 from vllm.model_executor.model_loader.loader import (RunaiModelStreamerLoader,

tests/runai_model_streamer/test_weight_utils.py

+# SPDX-License-Identifier: Apache-2.0
+
 import glob
 import tempfile