Add ZYDIS_BUILD_TESTS option and include tests in CMakeLists.txt

[topazus]

No description provided.

[athre0z]

Thanks, that's good to have! I added two more commits to also rework our convenience Makefile and the CI to go via the CMake testing path for the sake of de-duplication.

Edit: Ah, there appear to be issues on Windows.. let me see if I can find out what's the issue there.

[athre0z]

Ok, it's also working on Windows now. I had to replace the literal python3 with the variable populated by find_package(Python ...), add generator expressions for the executable paths (on Windows the executables are placed into sub-directories of the output directory) and add if (TARGET xyz) guards to make sure it doesn't break when e.g. the encoder is disabled.

[topazus]

Thanks for the review and further improvement.