[heap] Do not invoke GC to make heap iterable.

src/profiler/heap-profiler.cc

Index: src/profiler/heap-profiler.cc
diff --git a/src/profiler/heap-profiler.cc b/src/profiler/heap-profiler.cc
index e048faece5401e7deacb41bf09ee2c73cefc0271..d01a15b040138ab417e4c1fda507ed049aad3c89 100644
--- a/src/profiler/heap-profiler.cc
+++ b/src/profiler/heap-profiler.cc
@@ -198,7 +198,7 @@ void HeapProfiler::SetRetainedObjectInfo(UniqueId id,
 
 Handle<HeapObject> HeapProfiler::FindHeapObjectById(SnapshotObjectId id) {
   HeapObject* object = NULL;
-  HeapIterator iterator(heap(), HeapIterator::kFilterUnreachable);
+  HeapIterator iterator(heap(), HeapObjectsFiltering::kFilterUnreachable);
   // Make sure that object with the given id is still reachable.
   for (HeapObject* obj = iterator.next();
        obj != NULL;