[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 ...

tests/compile/test_pass_manager.py

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

tests/compile/test_wrapper.py

+# SPDX-License-Identifier: Apache-2.0
+
 from typing import Optional
 
 import torch

tests/compile/utils.py

+# SPDX-License-Identifier: Apache-2.0
+
 import os
 
 import torch

tests/conftest.py

+# SPDX-License-Identifier: Apache-2.0
+
 import json
 import os
 import tempfile

tests/core/block/conftest.py

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

tests/core/block/e2e/conftest.py

+# SPDX-License-Identifier: Apache-2.0
+
 from typing import Callable, Iterable, Optional
 
 import pytest

tests/core/block/e2e/test_correctness.py

+# SPDX-License-Identifier: Apache-2.0
+
 from itertools import cycle
 
 import pytest

tests/core/block/e2e/test_correctness_sliding_window.py

+# SPDX-License-Identifier: Apache-2.0
+
 import random
 from typing import List
 

tests/core/block/test_block_manager.py

+# SPDX-License-Identifier: Apache-2.0
+
 import pytest
 
 from vllm.core.block.utils import (STR_NOT_IMPL_ENC_DEC_PREFIX_CACHE,

tests/core/block/test_block_table.py

+# SPDX-License-Identifier: Apache-2.0
+
 from typing import List
 
 import pytest

tests/core/block/test_common.py

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

tests/core/block/test_cpu_gpu_block_allocator.py

+# SPDX-License-Identifier: Apache-2.0
+
 import pytest
 
 from vllm.core.block.cpu_gpu_block_allocator import CpuGpuBlockAllocator

tests/core/block/test_naive_block.py

+# SPDX-License-Identifier: Apache-2.0
+
 from typing import List, Optional
 
 import pytest

tests/core/block/test_prefix_caching_block.py

+# SPDX-License-Identifier: Apache-2.0
+
 import math
 import random
 from typing import List, Optional

tests/core/test_chunked_prefill_scheduler.py

+# SPDX-License-Identifier: Apache-2.0
+
 from typing import List
 from unittest.mock import MagicMock
 

tests/core/test_num_computed_tokens_update.py

+# SPDX-License-Identifier: Apache-2.0
+
 import pytest
 
 from tests.conftest import VllmRunner

tests/core/test_scheduler.py

+# SPDX-License-Identifier: Apache-2.0
+
 import time
 from collections import deque
 from typing import List, Set, Tuple

tests/core/test_scheduler_encoder_decoder.py

+# SPDX-License-Identifier: Apache-2.0
+
 from typing import List
 
 import pytest  # noqa

tests/core/test_serialization.py

+# SPDX-License-Identifier: Apache-2.0
+
 import msgspec
 
 from vllm.executor.msgspec_utils import decode_hook, encode_hook

tests/core/utils.py

+# SPDX-License-Identifier: Apache-2.0
+
 import time
 from collections import defaultdict
 from typing import Any, Dict, List, Optional