Removed Thread 'dying' attribute.

There is no Thread API to put a thread into a 'dying' state, so any such
possible observation of a thread is a non-deterministic race.

kernel/bootstrap/thread.rb

@@ -194,8 +194,6 @@ def status
     if @alive
       if @sleep
         "sleep"
-      elsif @dying
-        "aborting"
       else
         "run"
       end
@@ -421,9 +419,7 @@ def __run__
         end
       end
     rescue Exception => e
-      # I don't really get this, but this is MRI's behavior. If we're dying
-      # by request, ignore any raised exception.
-      exception = e # unless @dying
+      exception = e
     ensure
       unless exception && (abort_on_exception || Thread.abort_on_exception)
         @exception = exception
@@ -445,7 +441,6 @@ def __run__
   end
 
   def kill
-    @dying = true
     @sleep = false
     Rubinius.synchronize(self) do
       kill_prim

vm/builtin/thread.cpp

@@ -67,7 +67,6 @@ namespace rubinius {
     thr->result(state, cFalse);
     thr->exception(state, nil<Exception>());
     thr->critical(state, cFalse);
-    thr->dying(state, cFalse);
     thr->joins(state, Array::create(state, 1));
     thr->killed(state, cFalse);
     thr->priority(state, Fixnum::from(0));

vm/builtin/thread.hpp

@@ -44,7 +44,6 @@ namespace rubinius {
     Object* result_; // slot
     Exception* exception_; // slot
     Object* critical_; // slot
-    Object* dying_; // slot
     Array* joins_; // slot
     Object* killed_; // slot
     Fixnum* priority_; // slot
@@ -84,7 +83,6 @@ namespace rubinius {
     attr_accessor(result, Object);
     attr_accessor(exception, Exception);
     attr_accessor(critical, Object);
-    attr_accessor(dying, Object);
     attr_accessor(joins, Array);
     attr_accessor(killed, Object);
     attr_accessor(priority, Fixnum);