layernorm fix

orttraining/orttraining/python/training/ortmodule/_custom_op_symbolic_registry.py

@@ -817,18 +817,8 @@ def layer_norm(g, input, normalized_shape, weight, bias, eps, cudnn_enable):
     # layer_norm normalizes on the last D dimensions,
     # where D is the size of normalized_shape
     axis = -len(normalized_shape)
-    scalar_type = _type_utils.JitScalarType.from_value(
-        input, _type_utils.JitScalarType.FLOAT
-    )
-    dtype = scalar_type.dtype()
-    if symbolic_helper._is_none(weight):
-        weight_value = torch.ones(normalized_shape, dtype=dtype)
-        weight = g.op("Constant", value_t=weight_value)
-    if symbolic_helper._is_none(bias):
-        bias_value = torch.zeros(normalized_shape, dtype=dtype)
-        bias = g.op("Constant", value_t=bias_value)
-
-    out = g.op(
+
+    res, new_running_mean, new_running_var = g.op(
         "LayerNormalization",
         input,
         weight,
@@ -840,5 +830,4 @@ def layer_norm(g, input, normalized_shape, weight, bias, eps, cudnn_enable):
         overload_name_s="vec",
     )
 
-    res, new_running_mean, new_running_var = out
-    return res, new_running_mean, new_running_var
+    return res