Do not clear weak monomorphic IC after context disposal.

BUG=404020
LOG=Y
R=jochen@chromium.org

Review URL: https://codereview.chromium.org/525343002

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@23564 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

src/heap/objects-visiting-inl.h

@@ -261,7 +261,8 @@ void StaticMarkingVisitor<StaticVisitor>::VisitCodeTarget(Heap* heap,
   // to be serialized.
   if (FLAG_cleanup_code_caches_at_gc && target->is_inline_cache_stub() &&
       (target->ic_state() == MEGAMORPHIC || target->ic_state() == GENERIC ||
-       target->ic_state() == POLYMORPHIC || heap->flush_monomorphic_ics() ||
+       target->ic_state() == POLYMORPHIC ||
+       (heap->flush_monomorphic_ics() && !target->is_weak_stub()) ||
        heap->isolate()->serializer_enabled() ||
        target->ic_age() != heap->global_ic_age() ||
        target->is_invalidated_weak_stub())) {