[DO NOT LAND] Set @@toStringTag for DOM object prototypes

Source/bindings/tests/results/core/V8TestObject.cpp

Index: Source/bindings/tests/results/core/V8TestObject.cpp
diff --git a/Source/bindings/tests/results/core/V8TestObject.cpp b/Source/bindings/tests/results/core/V8TestObject.cpp
index c832bc473c3960944770847bb1f6553c21bb0ed5..434f47e1766437d93a0b2c0ba2b7fc4cad99dcd6 100644
--- a/Source/bindings/tests/results/core/V8TestObject.cpp
+++ b/Source/bindings/tests/results/core/V8TestObject.cpp
@@ -13017,6 +13017,8 @@ static void installV8TestObjectTemplate(v8::Local<v8::FunctionTemplate> function
     functionTemplate->SetNativeDataProperty(v8AtomicString(isolate, "staticStringAttribute"), TestObjectV8Internal::staticStringAttributeAttributeGetterCallback, TestObjectV8Internal::staticStringAttributeAttributeSetterCallback, v8::External::New(isolate, 0), static_cast<v8::PropertyAttribute>(v8::None), v8::Local<v8::AccessorSignature>(), static_cast<v8::AccessControl>(v8::DEFAULT));
     functionTemplate->SetNativeDataProperty(v8AtomicString(isolate, "staticLongAttribute"), TestObjectV8Internal::staticLongAttributeAttributeGetterCallback, TestObjectV8Internal::staticLongAttributeAttributeSetterCallback, v8::External::New(isolate, 0), static_cast<v8::PropertyAttribute>(v8::None), v8::Local<v8::AccessorSignature>(), static_cast<v8::AccessControl>(v8::DEFAULT));
 
+    prototypeTemplate->Set(v8::Symbol::GetToStringTag(isolate), v8AtomicString(isolate, "TestObject"));
+
     // Custom toString template
     functionTemplate->Set(v8AtomicString(isolate, "toString"), V8PerIsolateData::from(isolate)->toStringTemplate());
 }