The main problem was that string array objects were constructed
differently:
- if constructed by the test, then the elements were constant
- if constructed by the plugin, then the elements were allocated
Modified it so that now each array contains allocated strings so
they can be handled similarly. For freeing, I have used the
str_array_free function from the plugin, so I have linked its object
into the test runner.
Happy path is now free of "definitely lost" memleaks, so the test
can be used for valgrind.
