Do not clear weak monomorphic IC after context disposal.

src/heap/objects-visiting-inl.h

Index: src/heap/objects-visiting-inl.h
diff --git a/src/heap/objects-visiting-inl.h b/src/heap/objects-visiting-inl.h
index 8846d27bceb4e9f4b9a0eeaa219457209889d88d..7fe6a508b12f628a0fe0b275e8260297366a4b5b 100644
--- a/src/heap/objects-visiting-inl.h
+++ b/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())) {