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

Source/bindings/tests/results/core/V8TestInterface2.cpp

Index: Source/bindings/tests/results/core/V8TestInterface2.cpp
diff --git a/Source/bindings/tests/results/core/V8TestInterface2.cpp b/Source/bindings/tests/results/core/V8TestInterface2.cpp
index 96e90f19dfc92bbd270efbdd09b425f2cb249d85..29198b3b3179049e8bbb2aa6889283dcfb90cd4e 100644
--- a/Source/bindings/tests/results/core/V8TestInterface2.cpp
+++ b/Source/bindings/tests/results/core/V8TestInterface2.cpp
@@ -664,6 +664,8 @@ static void installV8TestInterface2Template(v8::Local<v8::FunctionTemplate> func
     static const V8DOMConfiguration::SymbolKeyedMethodConfiguration symbolKeyedIteratorConfiguration = { v8::Symbol::GetIterator, TestInterface2V8Internal::iteratorMethodCallback, 0, V8DOMConfiguration::ExposedToAllScripts };
     V8DOMConfiguration::installMethod(isolate, prototypeTemplate, defaultSignature, v8::DontDelete, symbolKeyedIteratorConfiguration);
 
+    prototypeTemplate->Set(v8::Symbol::GetToStringTag(isolate), v8AtomicString(isolate, "TestInterface2"));
+
     // Custom toString template
     functionTemplate->Set(v8AtomicString(isolate, "toString"), V8PerIsolateData::from(isolate)->toStringTemplate());
 }