Simplify FrameMap: make offsets of spill slots and outgoing parameters independent so that they can be allocated at the same time, eliminating the separate phases. This makes the separate StackBlock unnecesary. Change CiStackSlot to use byte offsets instead of spill slot index. This makes CiTarget.spillSlotSize unnecessary.

// A simple class to extend an abstract class and get loaded with different
// loaders.  This class is loaded via LOADER2.
public class from_loader2 implements IFace {
  public many_loader[] gen() {
    many_loader[] x = new many_loader[1];
    x[0] = new many_loader();
    return x;
  }
}