Add tests using kotlinx-lincheck

[lukaszstolarczuk]

Extra tests for concurrent data structures using kotlinx-lincheck should be fairly easy.
And BTW it will show compatibility of our code with Kotlin.

[lukaszstolarczuk]

After all, it wasn't as simple as previously thought (or maybe it's just me 😄 ).

#150

// old, perhaps useful links:
example test
string generation