Add Graal Native Image tests to CI

[CedNaru]

It often happens that we add/change/delete Kotlin methods called from C++ using JNI. Graal Native Image needs an exact configuration file of all methods called this way (because statically linked), it's easy to forget as we do most of our local testing in the JVM (because iterations are much faster). To prevent those mistakes we should build and run tests for native images the same way we currently do for the JVM.