before optimising function result assignment, because at this point the
hidden self parameter is not yet inserted (mantis #12597)
* changed ttypeconvnode.actualtargetnode to use the same logic as what
is used to determine whether something can be assigned to the result
of a type conversion (so the above check also works if the methodpointer
contains a typecast to a different object type)
git-svn-id: trunk@12038 -