message: fix UT failed in GCC 9.1.1
diff: @@ -534,6 +534,10 @@ TEST(BalanceTest, SpecifyMultiHostTest) {
  ASSERT_EQ(cpp2::ErrorCode::SUCCEEDED, resp.code);
  ASSERT_EQ(1, resp.get_id().get_space_id());
  }
  + std::unordered_map<HostAddr, int32_t> partCount;
  + for (int32_t i = 0; i < 6; i++) {
  + partCount[HostAddr(i, i)] = 6;
  + }
  std::vector<Status> sts(9, Status::OK());
  std::unique_ptr<FaultInjector> injector(new TestFaultInjector(std::move(sts)));
  auto client = std::make_unique<AdminClient>(std::move(injector));
  @@ -578,7 +582,9 @@ TEST(BalanceTest, SpecifyMultiHostTest) {
  task.spaceId_ = std::get<1>(tup);
  ASSERT_EQ(1, task.spaceId_);
  task.src_ = std::get<3>(tup);
  - ASSERT_TRUE(task.src_ == HostAddr(2, 2) || task.src_ == HostAddr(3, 3));
  + task.dst_ = std::get<4>(tup);
  + partCount[task.src_]--;
  + partCount[task.dst_]++;
  }
  {
  auto tup = BalanceTask::parseVal(iter->val());
  @@ -594,8 +600,13 @@ TEST(BalanceTest, SpecifyMultiHostTest) {
  num++;
  iter->next();
  }
  - ASSERT_EQ(12, num);
  }
  + ASSERT_EQ(9, partCount[HostAddr(0, 0)]);
  + ASSERT_EQ(9, partCount[HostAddr(1, 1)]);
  + ASSERT_EQ(0, partCount[HostAddr(2, 2)]);
  + ASSERT_EQ(0, partCount[HostAddr(3, 3)]);
  + ASSERT_EQ(9, partCount[HostAddr(4, 4)]);
  + ASSERT_EQ(9, partCount[HostAddr(5, 5)]);
  }
  TEST(BalanceTest, RecoveryTest) {
  