[simplefsdp] fix comm placeholder input bug

torch/_inductor/fx_passes/bucketing.py

@@ -138,6 +138,7 @@ def is_wait_tensor(node: torch.fx.Node) -> bool:
     return (
         node.op == "call_function"
         and node.target is torch.ops._c10d_functional.wait_tensor.default
+        and node.args[0].op == "call_function"
     )