Switch UnreachableObjectsFilter to use Marking instead of InstrusiveMarking.

src/heap.h

 // Copyright 2011 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 1936 matching lines @@
 // objects that still remain in the heap). As implementation of free
 // nodes filtering uses GC marks, it can't be used during MS/MC GC
 // phases. Also, it is forbidden to interrupt iteration in this mode,
 // as this will leave heap objects marked (and thus, unusable).
 class HeapObjectsFilter;
 
 class HeapIterator BASE_EMBEDDED {
  public:
   enum HeapObjectsFiltering {
     kNoFiltering,
-    kFilterFreeListNodes,
     kFilterUnreachable
   };
 
   HeapIterator();
   explicit HeapIterator(HeapObjectsFiltering filtering);
   ~HeapIterator();
 
   HeapObject* next();
   void reset();
 
@@ skipping 500 matching lines @@
 
   DISALLOW_IMPLICIT_CONSTRUCTORS(PathTracer);
 };
 #endif  // DEBUG || LIVE_OBJECT_LIST
 
 } }  // namespace v8::internal
 
 #undef HEAP
 
 #endif  // V8_HEAP_H_