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

Source/bindings/tests/results/core/V8TestInterfaceGarbageCollected.cpp

Index: Source/bindings/tests/results/core/V8TestInterfaceGarbageCollected.cpp
diff --git a/Source/bindings/tests/results/core/V8TestInterfaceGarbageCollected.cpp b/Source/bindings/tests/results/core/V8TestInterfaceGarbageCollected.cpp
index 0054822a25477295008910243675d1350e99abf0..df6b7895f0e3729234c587e235c6be0f338a7bb8 100644
--- a/Source/bindings/tests/results/core/V8TestInterfaceGarbageCollected.cpp
+++ b/Source/bindings/tests/results/core/V8TestInterfaceGarbageCollected.cpp
@@ -382,6 +382,10 @@ static void installV8TestInterfaceGarbageCollectedTemplate(v8::Local<v8::Functio
     static const V8DOMConfiguration::SymbolKeyedMethodConfiguration symbolKeyedIteratorConfiguration = { v8::Symbol::GetIterator, TestInterfaceGarbageCollectedV8Internal::iteratorMethodCallback, 0, V8DOMConfiguration::ExposedToAllScripts };
     V8DOMConfiguration::installMethod(isolate, prototypeTemplate, defaultSignature, v8::DontDelete, symbolKeyedIteratorConfiguration);
 
+    instanceTemplate->Set(v8::Symbol::GetToStringTag(isolate), v8AtomicString(isolate, "TestInterfaceGarbageCollected"));
+
+    prototypeTemplate->Set(v8::Symbol::GetToStringTag(isolate), v8AtomicString(isolate, "TestInterfaceGarbageCollectedPrototype"));
+
     // Custom toString template
     functionTemplate->Set(v8AtomicString(isolate, "toString"), V8PerIsolateData::from(isolate)->toStringTemplate());
 }