[Misc] Fix improper placement of SPDX header in scripts (#12694)

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

cmake/hipify.py

-# SPDX-License-Identifier: Apache-2.0
-
 #!/usr/bin/env python3
+# SPDX-License-Identifier: Apache-2.0
 
 #
 # A command line tool for running pytorch's hipify preprocessor on CUDA

tests/models/test_transformers.py

+# SPDX-License-Identifier: Apache-2.0
 """Test the functionality of the Transformers backend.
 
 Run `pytest tests/models/test_transformers.py`.

tools/check_spdx_header.py

@@ -10,18 +10,25 @@ def check_spdx_header(file_path):
     with open(file_path, encoding='UTF-8') as file:
         lines = file.readlines()
         if not lines:
-            # not necessary for an empty file like __init__.py
+            # Empty file like __init__.py
             return True
-        if not lines[0].strip().startswith(SPDX_HEADER_PREFIX):
-            return False
+        for line in lines:
+            if line.strip().startswith(SPDX_HEADER_PREFIX):
                 return True
+    return False
 
 
 def add_header(file_path):
     with open(file_path, 'r+', encoding='UTF-8') as file:
         lines = file.readlines()
         file.seek(0, 0)
-        file.write(SPDX_HEADER + '\n\n' + ''.join(lines))
+        if lines and lines[0].startswith("#!"):
+            file.write(lines[0])
+            file.write(SPDX_HEADER + '\n')
+            file.writelines(lines[1:])
+        else:
+            file.write(SPDX_HEADER + '\n')
+            file.writelines(lines)
 
 
 def main():

tools/report_build_time_ninja.py

+#!/usr/bin/env python3
 # SPDX-License-Identifier: Apache-2.0
 
-#!/usr/bin/env python3
 # Copyright (c) 2018 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.

vllm/attention/ops/triton_flash_attention.py

-# SPDX-License-Identifier: Apache-2.0
-
 #!/usr/bin/env python
+# SPDX-License-Identifier: Apache-2.0
 """
 Fused Attention
 ===============

vllm/model_executor/models/transformers.py

+# SPDX-License-Identifier: Apache-2.0
 # Copyright 2024 The vLLM team.
 #
 # Licensed under the Apache License, Version 2.0 (the "License");