Fix bindings when using [CachedAttribute] on Array.

Source/bindings/templates/attributes.cpp

 {##############################################################################}
 {% macro attribute_getter(attribute, world_suffix) %}
 {% filter conditional(attribute.conditional_string) %}
 static void {{attribute.name}}AttributeGetter{{world_suffix}}(
 {%- if attribute.is_expose_js_accessors %}
 const v8::FunctionCallbackInfo<v8::Value>& info
 {%- else %}
 const v8::PropertyCallbackInfo<v8::Value>& info
 {%- endif %})
 {
@@ skipping 77 matching lines @@
     {% if attribute.has_type_checking_nullable %}
     if (!{{attribute.cpp_value}}) {
     {% else %}
     if (isNull) {
     {% endif %}
         v8SetReturnValueNull(info);
         return;
     }
     {% endif %}
     {% if attribute.cached_attribute_validation_method %}
-    V8HiddenValue::setHiddenValue(info.GetIsolate(), holder, propertyName, {{attribute.cpp_value}}.v8Value());
+    V8HiddenValue::setHiddenValue(info.GetIsolate(), holder, propertyName, {{attribute.cpp_value_to_v8_value}});
     {% endif %}
     {# v8SetReturnValue #}
     {% if attribute.is_keep_alive_for_gc %}
     {# FIXME: merge local variable assignment with above #}
     {{attribute.cpp_type}} result({{attribute.cpp_value}});
     if (result && DOMDataStore::setReturnValueFromWrapper{{world_suffix}}<{{attribute.v8_type}}>(info.GetReturnValue(), result.get()))
         return;
     v8::Handle<v8::Value> wrapper = toV8(result.get(), holder, info.GetIsolate());
     if (!wrapper.IsEmpty()) {
         V8HiddenValue::setHiddenValue(info.GetIsolate(), holder, v8AtomicString(info.GetIsolate(), "{{attribute.name}}"), wrapper);
@@ skipping 233 matching lines @@
     {% endif %}
     {% if attribute.has_custom_setter %}
     {{v8_class}}::{{attribute.name}}AttributeSetterCustom(v8Value, info);
     {% else %}
     {{cpp_class}}V8Internal::{{attribute.name}}AttributeSetter{{world_suffix}}(v8Value, info);
     {% endif %}
     TRACE_EVENT_SET_SAMPLING_STATE("V8", "V8Execution");
 }
 {% endfilter %}
 {% endmacro %}