message: Fix index data for Mixed/float to handle int equality
diff: @@ -529,6 +529,10 @@ StringData Mixed::get_index_data(std::array<char, 16>& buffer) const
  }
  case type_Float: {
  auto v2 = get_float();
  + int i = int(v2);
  + if (i == v2) {
  + return Mixed(i).get_index_data(buffer);
  + }
  const char* src = reinterpret_cast<const char*>(&v2);
  realm::safe_copy_n(src, sizeof(float), buffer.data());
  return StringData{buffer.data(), sizeof(float)};
  