[Bugfix] Fix GPT-OSS AR+NORM fusion (#28841)

Signed-off-by: elvischenv <219235043+elvischenv@users.noreply.github.com>

tests/compile/distributed/test_fusions_e2e.py

@@ -111,6 +111,17 @@ if current_platform.is_cuda():
                 async_tp=96,  # MLP is MoE, half the fusions of dense
             ),
         ),
+        ModelBackendTestCase(
+            model_name="openai/gpt-oss-20b",
+            model_kwargs=dict(max_model_len=1024, kv_cache_dtype="fp8"),
+            backend=AttentionBackendEnum.FLASHINFER,
+            matches=Matches(
+                attention_fusion=0,
+                allreduce_fusion=49,
+                sequence_parallel=49,
+                async_tp=48,
+            ),
+        ),
     ]
 
 elif current_platform.is_rocm():