message: Add Shape operator to quantization support whitelist
  This op doesn't care about the type of the inputs, so add it to the
  quanitization support whitelist.
  This partially addresses (Cast is still unsupported)
diff: @@ -61,7 +61,8 @@ bool SupportsQuantization(const Operator& op) {
  type == OperatorType::kGreaterEqual || type == OperatorType::kLess ||
  type == OperatorType::kLessEqual || type == OperatorType::kSelect ||
  type == OperatorType::kArgMax || type == OperatorType::kRelu ||
  - type == OperatorType::kRelu1 || type == OperatorType::kRelu6;
  + type == OperatorType::kRelu1 || type == OperatorType::kRelu6 ||
  + type == OperatorType::kShape;
  }
  // The quantized op allows output arrays of type float using
  