Transfer multicast address used for tests from Arguments class to test class 

In aPull request, SonarQube triggers warning "Make sure using this hardcoded IP address is safe here." (cpp:S1313) because we define:
```cpp
 auto networkLevelMulticastAddressForTests{"239.255.0.1"};
```
in `Arguments.cpp`.

It would be cleaner to define this value only in test class `TcpTest.cpp`.