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

Source/bindings/tests/results/core/V8TestInterface.cpp

Index: Source/bindings/tests/results/core/V8TestInterface.cpp
diff --git a/Source/bindings/tests/results/core/V8TestInterface.cpp b/Source/bindings/tests/results/core/V8TestInterface.cpp
index 45552e8b108c58b35de1bd2adfe577a7e1a5dd80..2953be8857fa54cc45b660911f0756ae7eed6159 100644
--- a/Source/bindings/tests/results/core/V8TestInterface.cpp
+++ b/Source/bindings/tests/results/core/V8TestInterface.cpp
@@ -2451,6 +2451,8 @@ void V8TestInterface::installV8TestInterfaceTemplate(v8::Local<v8::FunctionTempl
 #endif // ENABLE(PARTIAL_CONDITION)
     functionTemplate->SetNativeDataProperty(v8AtomicString(isolate, "partial2StaticLongAttribute"), TestInterfaceImplementationV8Internal::partial2StaticLongAttributeAttributeGetterCallback, TestInterfaceImplementationV8Internal::partial2StaticLongAttributeAttributeSetterCallback, 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, "TestInterface"));
+
     // Custom toString template
     functionTemplate->Set(v8AtomicString(isolate, "toString"), V8PerIsolateData::from(isolate)->toStringTemplate());
 }