message: Check bias tensor ID in XNNPACK delegate
  Verify that bias tensor ID in CONV_2D, DEPTHWISE_CONV_2D, and FULLY_CONNECTED
  nodes is non-negative. If the check fails, interpret it as missing bias input,
  and reject delegating the node without any out-of-bound access.
diff: @@ -1231,7 +1231,14 @@ class Subgraph {
  logging_context, filter_tensor, node->inputs->data[1], node_index));
  }
  - const TfLiteTensor& bias_tensor = tensors[node->inputs->data[2]];
  + const int bias_tensor_id = node->inputs->data[2];
  + if (bias_tensor_id < 0) {
  + TF_LITE_MAYBE_KERNEL_LOG(logging_context,
  + "unsupported CONV_2D node #%d without bias",
  + node_index);
  + return kTfLiteError;
  + }
  + const TfLiteTensor& bias_tensor = tensors[bias_tensor_id];
  TF_LITE_ENSURE_STATUS(CheckTensorFloatType(
  logging_context, bias_tensor, node->inputs->data[2], node_index));
  TF_LITE_ENSURE_STATUS(CheckTensorShape(logging_context, bias_tensor, 1,
  @@ -1319,7 +1326,14 @@ class Subgraph {
  logging_context, filter_tensor, node->inputs->data[1], node_index));
  }
  - const TfLiteTensor& bias_tensor = tensors[node->inputs->data[2]];
  + const int bias_tensor_id = node->inputs->data[2];
  + if (bias_tensor_id < 0) {
  + TF_LITE_MAYBE_KERNEL_LOG(
  + logging_context,
  + "unsupported DEPTHWISE_CONV_2D node #%d without bias", node_index);
  + return kTfLiteError;
  + }
  + const TfLiteTensor& bias_tensor = tensors[bias_tensor_id];
  TF_LITE_ENSURE_STATUS(CheckTensorFloatType(
  logging_context, filter_tensor, node->inputs->data[2], node_index));
  TF_LITE_ENSURE_STATUS(CheckTensorShape(logging_context, bias_tensor, 1,
  @@ -1503,7 +1517,14 @@ class Subgraph {
  logging_context, filter_tensor, node->inputs->data[1], node_index));
  }
  - const TfLiteTensor& bias_tensor = tensors[node->inputs->data[2]];
  + const int bias_tensor_id = node->inputs->data[2];
  + if (bias_tensor_id < 0) {
  + TF_LITE_MAYBE_KERNEL_LOG(
  + logging_context, "unsupported FULLY_CONNECTED node #%d without bias",
  + node_index);
  + return kTfLiteError;
  + }
  + const TfLiteTensor& bias_tensor = tensors[bias_tensor_id];
  TF_LITE_ENSURE_STATUS(CheckTensorFloatType(
  logging_context, filter_tensor, node->inputs->data[2], node_index));
  TF_LITE_ENSURE_STATUS(CheckTensorShape(logging_context, bias_tensor, 1,
  