message: Add tf.Add op
  Add ops.td for TF dialect and start by adding tf.Add (op used in legalizer pattern). This CL does not add TensorOp trait (that's not part of OpTrait namespace).
  Remove OpCode emission that is not currently used and can be added back later if needed.
diff: @@ -520,15 +520,6 @@ void OpEmitter::emitTraits() {
  static void emitOpClasses(const RecordKeeper &recordKeeper,
  const std::vector<Record *> &defs, raw_ostream &os) {
  IfDefScope scope("GET_OP_CLASSES", os);
  -
  - // Enumeration of all the ops defined.
  - os << "enum class OpCode {\n";
  - for (int i = 0, e = defs.size(); i != e; ++i) {
  - auto &def = defs[i];
  - os << (i != 0 ? "," : "") << "k" << def->getName();
  - }
  - os << "\n};\n";
  -
  for (auto *def : defs)
  OpEmitter::emit(*def, os);
  }
  