message: Rename ALPHA to kALPHA and make constexpr
diff: @@ -2189,16 +2189,16 @@ TEST_F(OpConverterTest, ConvertActivation) {
  "Relu is only implemented for tensors, at my_act");
  }
  - const float ALPHA = 0.2f;
  + constexpr float kALPHA = 0.2f;
  // Get nodedef for activation layer.
  - auto get_act_nodedef = [ALPHA](string op_name) -> NodeDef {
  + auto get_act_nodedef = [](string op_name) -> NodeDef {
  Scope s = Scope::NewRootScope();
  auto input = ops::Placeholder(s.WithOpName("input"), DT_FLOAT);
  if (op_name == "LeakyRelu") {
  // LeakyRelu does not have a C++ API
  NodeDef node_def = MakeNodeDef("my_act", "LeakyRelu", {"input"});
  - (*node_def.mutable_attr())["alpha"].set_f(ALPHA);
  + (*node_def.mutable_attr())["alpha"].set_f(kALPHA);
  return node_def;
  } else if (op_name == "Relu") {
  auto act = ops::Relu(s.WithOpName("my_act"), input);
  @@ -2214,9 +2214,9 @@ TEST_F(OpConverterTest, ConvertActivation) {
  return NodeDef();
  };
  // Get expected output for activation layer.
  - auto get_act_output = [ALPHA](string op_name, float input) -> float {
  + auto get_act_output = [](string op_name, float input) -> float {
  if (op_name == "LeakyRelu") {
  - return (input > 0.0f) ? input : input * ALPHA;
  + return (input > 0.0f) ? input : input * kALPHA;
  } else if (op_name == "Relu") {
  return (input > 0.0f) ? input : 0.0f;
  } else if (op_name == "Sigmoid") {
  