Random test generator improvments
Random test generator improvments

- Support unary operations move, clz, ctz
- Support negative immediate values
- Use endswidth instead of [:-2]

FulcronZ/NyuziProcessor,jbush001/NyuziProcessor,jbush001/NyuziProcessor,jbush001/NyuziProcessor,hoangt/NyuziProcessor,jbush001/NyuziProcessor,hoangt/NyuziProcessor,FulcronZ/NyuziProcessor,jbush001/NyuziProcessor,hoangt/NyuziProcessor,hoangt/NyuziProcessor,FulcronZ/NyuziProcessor,jbush001/NyuziProcessor,FulcronZ/NyuziProcessor