Error when running ./all_tests on Linux

The following error was encountered while testing ```./all_tests``` on Linux.

The command I run is as follow (```${my_StarCraftII_path} and ${my_s2client-api_path}``` denote the path of my StarCraftII and s2client-api, respectively):

```shell
./all_tests -e ${my_StarCraftII_path}/Versions/Base69232/SC2_x64
```
And the output of this command are as follows:

```shell
Running test: sc2::TestAbilityRemap
Launched SC2 (${my_StarCraftII_path}/Versions/Base69232/SC2_x64), PID: 145940
${my_StarCraftII_path}/Versions/Base69232/SC2_x64: /lib64/libstdc++.so.6: version GLIBCXX_3.4.21' not found (required by ${my_StarCraftII_path}/Versions/Base69232/SC2_x64)
Waiting for connection.....................................................................................
...................................
Unable to connect to game all_tests: ${my_s2client-api_path}/src/sc2api/sc2_coordinator.cc:94: bool sc2::AttachClients(sc2::ProcessSettings&, std::vector): Assertion connected' failed.
Aborted
```

It's quite strange that I got "/lib64/libstdc++.so.6: version `GLIBCXX_3.4.21' not found (required by ${my_StarCraftII_path}/Versions/Base69232/SC2_x64)" when launching SC2, as I can start SC2 manually by following commands:

```shell
cd ${my_StarCraftII_path}/Versions/Base69232/
./SC2_x64 -listen 127.0.0.1 -port 37688
```

And the output of the commands are:
```shell
Version: B69232 (SC2.4.6-Publish)
Build: Oct 23 2018 01:43:04
Command Line: '"./SC2_x64" -listen 127.0.0.1 -port 37688'
Starting up...
Startup Phase 1 complete
Startup Phase 2 complete
Creating stub renderer...
Listening on: 127.0.0.1:37688
Startup Phase 3 complete. Ready for commands.
```
In my opinion, SC2 is started by this way in my Linux.
Besides, SC2 can also be started by other ways like python interface shown in [pysc2](https://github.com/deepmind/pysc2) and [smac](https://github.com/oxwhirl/smac). So I think my StarCraftII can work properly.

So, why won't StarCraft II start when I run ```./all_tests```?