[bugfix] [ROCm] Fix premature CUDA initialization in platform detection (#33941)

Signed-off-by: Kourosh Hakhamaneshi <kourosh@anyscale.com>

tests/cuda/scripts/check_platform_no_cuda_init.py

@@ -0,0 +1,20 @@
+#!/usr/bin/env python3
+# SPDX-License-Identifier: Apache-2.0
+# SPDX-FileCopyrightText: Copyright contributors to the vLLM project
+"""Check that vllm.platforms import does not initialize CUDA."""
+
+import os
+
+for key in ["CUDA_VISIBLE_DEVICES", "HIP_VISIBLE_DEVICES", "ROCR_VISIBLE_DEVICES"]:
+    os.environ.pop(key, None)
+
+import torch  # noqa: E402
+
+assert not torch.cuda.is_initialized(), "CUDA initialized before import"
+
+from vllm.platforms import current_platform  # noqa: E402
+
+assert not torch.cuda.is_initialized(), (
+    f"CUDA was initialized during vllm.platforms import on {current_platform}"
+)
+print("OK")