[CI/Build] Restore streaming executor fixture contract (#8418)

Signed-off-by: princepride <wangzhipeng628@gmail.com>

tests/diffusion/streaming_interactive_generation/test_diffusion_streaming_output.py

@@ -77,6 +77,7 @@ class _PipelineBackedEngine:
     def __init__(self, pipeline: _StepStreamingPipeline | _FailingStreamingPipeline) -> None:
         self.pipeline = pipeline
         self.executor = SimpleNamespace(
+            is_dead=False,
             register_failure_callback=MagicMock(),
             check_health=MagicMock(),
         )
@@ -127,9 +128,9 @@ def _streaming_diffusion_output(
 
 def _streaming_payload_and_metadata(output: DiffusionOutput) -> tuple[dict, dict]:
     envelope = output.output if isinstance(output.output, dict) else {}
-    payload = envelope.get("payload") if isinstance(envelope.get("payload"), dict) else {}
-    metadata = envelope.get("metadata") if isinstance(envelope.get("metadata"), dict) else {}
-    return payload, metadata
+    payload = envelope.get("payload")
+    metadata = envelope.get("metadata")
+    return payload if isinstance(payload, dict) else {}, metadata if isinstance(metadata, dict) else {}
 
 
 class TestPipelineStreamingOutputToStageDiffusionClient:
@@ -230,7 +231,7 @@ class TestPipelineStreamingOutputToStageDiffusionClient:
         client._response_socket.bind(response_address)
         client._encoder = OmniMsgpackEncoder()
         client._decoder = OmniMsgpackDecoder()
-        client._output_queue: asyncio.Queue[OmniRequestOutput] = asyncio.Queue()
+        client._output_queue = asyncio.Queue[OmniRequestOutput]()
         client._rpc_results = {}
         client._pending_rpcs = set()
         client._tasks = {}