[Misc] Add SPDX-FileCopyrightText (#19100)

Signed-off-by: simon-mo <simon.mo@hey.com>

tests/spec_decode/conftest.py

 # SPDX-License-Identifier: Apache-2.0
+# SPDX-FileCopyrightText: Copyright contributors to the vLLM project
 import pytest
 
 

tests/spec_decode/e2e/conftest.py

 # SPDX-License-Identifier: Apache-2.0
+# SPDX-FileCopyrightText: Copyright contributors to the vLLM project
 
 from collections.abc import Sequence
 from itertools import cycle

tests/spec_decode/e2e/test_compatibility.py

 # SPDX-License-Identifier: Apache-2.0
+# SPDX-FileCopyrightText: Copyright contributors to the vLLM project
 
 import pytest
 

tests/spec_decode/e2e/test_eagle_correctness.py

 # SPDX-License-Identifier: Apache-2.0
+# SPDX-FileCopyrightText: Copyright contributors to the vLLM project
 """This docstring details important information on the testing methodology.
 
 Most of the tests rely on "greedy equality", where we expect the output of

tests/spec_decode/e2e/test_integration.py

 # SPDX-License-Identifier: Apache-2.0
+# SPDX-FileCopyrightText: Copyright contributors to the vLLM project
 """Tests which cover integration of the speculative decoding framework with
 other features, e.g. cuda graphs.
 """

tests/spec_decode/e2e/test_integration_dist_tp2.py

 # SPDX-License-Identifier: Apache-2.0
+# SPDX-FileCopyrightText: Copyright contributors to the vLLM project
 """Tests which cover integration of the speculative decoding framework with
 tensor parallelism.
 """

tests/spec_decode/e2e/test_integration_dist_tp4.py

 # SPDX-License-Identifier: Apache-2.0
+# SPDX-FileCopyrightText: Copyright contributors to the vLLM project
 """Tests which cover integration of the speculative decoding framework with
 tensor parallelism.
 """

tests/spec_decode/e2e/test_logprobs.py

 # SPDX-License-Identifier: Apache-2.0
+# SPDX-FileCopyrightText: Copyright contributors to the vLLM project
 
 from itertools import cycle
 

tests/spec_decode/e2e/test_medusa_correctness.py

 # SPDX-License-Identifier: Apache-2.0
+# SPDX-FileCopyrightText: Copyright contributors to the vLLM project
 """This docstring details important information on the testing methodology.
 
 Most of the tests rely on "greedy equality", where we expect the output of

tests/spec_decode/e2e/test_mlp_correctness.py

 # SPDX-License-Identifier: Apache-2.0
+# SPDX-FileCopyrightText: Copyright contributors to the vLLM project
 """This docstring details important information on the testing methodology.
 
 Most of the tests rely on "greedy equality", where we expect the output of

tests/spec_decode/e2e/test_mtp_correctness.py

 # SPDX-License-Identifier: Apache-2.0
+# SPDX-FileCopyrightText: Copyright contributors to the vLLM project
 """This docstring details important information on the testing methodology.
 
 Most of the tests rely on "greedy equality", where we expect the output of

tests/spec_decode/e2e/test_multistep_correctness.py

 # SPDX-License-Identifier: Apache-2.0
+# SPDX-FileCopyrightText: Copyright contributors to the vLLM project
 """The tests in this file verify end-to-end speculative decoding correctness.
 
 This docstring details important information on the testing methodology.

tests/spec_decode/e2e/test_ngram_correctness.py

 # SPDX-License-Identifier: Apache-2.0
+# SPDX-FileCopyrightText: Copyright contributors to the vLLM project
 """This docstring details important information on the testing methodology.
 
 Most of the tests rely on "greedy equality", where we expect the output of

tests/spec_decode/e2e/test_seed.py

 # SPDX-License-Identifier: Apache-2.0
+# SPDX-FileCopyrightText: Copyright contributors to the vLLM project
 
 import pytest
 

tests/spec_decode/test_batch_expansion.py

 # SPDX-License-Identifier: Apache-2.0
+# SPDX-FileCopyrightText: Copyright contributors to the vLLM project
 
 import pytest
 import torch

tests/spec_decode/test_dynamic_spec_decode.py

 # SPDX-License-Identifier: Apache-2.0
+# SPDX-FileCopyrightText: Copyright contributors to the vLLM project
 
 from unittest.mock import MagicMock, patch
 

tests/spec_decode/test_memory_usage.py

 # SPDX-License-Identifier: Apache-2.0
+# SPDX-FileCopyrightText: Copyright contributors to the vLLM project
 """This docstring details important information on the testing methodology.
 
 This test verifies that memory usage remains constant (or never grows) when 

tests/spec_decode/test_metrics.py

 # SPDX-License-Identifier: Apache-2.0
+# SPDX-FileCopyrightText: Copyright contributors to the vLLM project
 
 import math
 from unittest.mock import MagicMock

tests/spec_decode/test_multi_step_worker.py

 # SPDX-License-Identifier: Apache-2.0
+# SPDX-FileCopyrightText: Copyright contributors to the vLLM project
 
 import random
 from unittest.mock import MagicMock

tests/spec_decode/test_ngram_worker.py

 # SPDX-License-Identifier: Apache-2.0
+# SPDX-FileCopyrightText: Copyright contributors to the vLLM project
 
 import torch