avoid name collision

Author: titaiwangms

onnxscript/rewriter/rules/common/_fuse_batchnorm.py

@@ -68,7 +68,9 @@ def rewrite(self, op, x: ir.Value, inbound_out: ir.Value, batchnorm_out: ir.Valu
             bias_name = inbound_node.inputs[2].name
         else:
             original_bias = np.zeros_like(input_mean)
-            bias_name = x.name + "_bias"
+            # Use inbound input 1 (should be weight) to derive a name for the bias
+            # to avoid name collision on initializer creation.
+            bias_name = inbound_node.inputs[1].name + "_bias"
         fused_bias = ir.tensor((original_bias - input_mean) * scale_factor + beta)
 
         return op.op(