[https://nvbugs/5741060][fix] Fix pg op test (NVIDIA#9989)

Signed-off-by: Shuyi Xiong <219646547+shuyixiong@users.noreply.github.com>

Author: shuyixiong

tests/integration/test_lists/waives.txt

@@ -442,7 +442,6 @@ accuracy/test_llm_api_pytorch.py::TestDeepSeekV3Lite::test_bfloat16_4gpus[tp2pp2
 unittest/_torch/modeling/test_modeling_out_of_tree.py::TestOutOfTree::test_llm_api[False] SKIP (https://nvbugs/5739981)
 unittest/_torch/modeling/test_modeling_out_of_tree.py::TestOutOfTree::test_llm_api[True] SKIP (https://nvbugs/5739981)
 unittest/_torch/modeling/test_modeling_out_of_tree.py::TestOutOfTree::test_serve[True] SKIP (https://nvbugs/5739981)
-unittest/_torch/ray_orchestrator/multi_gpu/test_ops.py SKIP (https://nvbugs/5741060)
 full:sm89/accuracy/test_disaggregated_serving.py::TestLlama3_1_8BInstruct::test_ctx_pp_gen_tp_asymmetric[MMLU-gen_tp=2-ctx_pp=2] SKIP (https://nvbugs/5596337)
 full:sm89/accuracy/test_disaggregated_serving.py::TestLlama3_1_8BInstruct::test_tp_pp_symmetric[MMLU-tp2pp2] SKIP (https://nvbugs/5596337)
 accuracy/test_llm_api_pytorch.py::TestQwen3_235B_A22B::test_nvfp4[latency_moe_trtllm] SKIP (https://nvbugs/5721672)

tests/unittest/_torch/ray_orchestrator/conftest.py

@@ -3,6 +3,11 @@
 
 import pytest
 
+try:
+    import ray
+except ModuleNotFoundError:
+    from tensorrt_llm import ray_stub as ray
+
 from tensorrt_llm._utils import mpi_disabled
 
 
@@ -21,3 +26,24 @@ def pytest_configure(config):
     pytest.skip(
         "Ray tests are only tested in Ray CI stage or with --run-ray flag",
         allow_module_level=True)
+
+
+@pytest.fixture(scope="function")
+def setup_ray_cluster():
+    runtime_env = {
+        "env_vars": {
+            "RAY_EXPERIMENTAL_NOSET_CUDA_VISIBLE_DEVICES": "1"
+        }
+    }
+    ray_init_args = {
+        "include_dashboard": False,
+        "namespace": "test",
+        "ignore_reinit_error": True,
+        "runtime_env": runtime_env
+    }
+    try:
+        ray.init(address="local", **ray_init_args)
+        yield
+    finally:
+        if ray.is_initialized():
+            ray.shutdown()