Change definition of `compiled-entry-kind' for return addresses. Now,

Change definition of `compiled-entry-kind' for return addresses.  Now,
the second element is a subtype: 0 means that the offset to the next
return address is fixed and known; 1 means that the next element on
the stack is a dynamic link, which points at the next return address;
and 2 means that this is the "return-to-interpreter" return address.
The third element is either a non-negative offset (for subtypes 0 and
2) or -1 (for subtype 1).