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

src/api.cc

Index: src/api.cc
diff --git a/src/api.cc b/src/api.cc
index a4e047c9b64a6b9c66c8618a3376f9a5ba12e540..076693d2c78b6cd58b80a0d579ac82580d62e877 100644
--- a/src/api.cc
+++ b/src/api.cc
@@ -397,7 +397,7 @@ StartupData SerializeIsolateAndContext(
   // GC may have cleared weak cells, so compact any WeakFixedArrays
   // found on the heap.
   i::HeapIterator iterator(internal_isolate->heap(),
-                           i::HeapIterator::kFilterUnreachable);
+                           i::HeapObjectsFiltering::kFilterUnreachable);
   for (i::HeapObject* o = iterator.next(); o != NULL; o = iterator.next()) {
     if (o->IsPrototypeInfo()) {
       i::Object* prototype_users = i::PrototypeInfo::cast(o)->prototype_users();