Make JSProxies always be in slow mode

test/cctest/test-dictionary.cc

Index: test/cctest/test-dictionary.cc
diff --git a/test/cctest/test-dictionary.cc b/test/cctest/test-dictionary.cc
index e1745c424c9c82ec18e4571d2ef8c2a10059268c..0d4edf5dd4756c53c66768f145d32e8f5807c1d7 100644
--- a/test/cctest/test-dictionary.cc
+++ b/test/cctest/test-dictionary.cc
@@ -228,4 +228,18 @@ TEST(ObjectHashTableCausesGC) {
 }
 #endif
 
+TEST(SetRequiresCopyOnCapacityChange) {
+  LocalContext context;
+  v8::HandleScope scope(context->GetIsolate());
+  Isolate* isolate = CcTest::i_isolate();
+  Handle<NameDictionary> dict = NameDictionary::New(isolate, 0, TENURED);
+  dict->SetRequiresCopyOnCapacityChange();
+  Handle<Name> key = isolate->factory()->InternalizeString(
+      v8::Utils::OpenHandle(*v8_str("key")));
+  Handle<Object> value = handle(Smi::FromInt(0), isolate);
+  Handle<NameDictionary> new_dict =
+      NameDictionary::Add(dict, key, value, PropertyDetails::Empty());
+  CHECK_NE(*dict, *new_dict);
+}
+
 }  // namespace