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

Source/bindings/tests/results/core/V8TestInterface3.cpp

Index: Source/bindings/tests/results/core/V8TestInterface3.cpp
diff --git a/Source/bindings/tests/results/core/V8TestInterface3.cpp b/Source/bindings/tests/results/core/V8TestInterface3.cpp
index 2d3d70b524c3f24d116fdb74a72275457895f944..477da7c9d922bd425b22f12d2f44b769090e2dc4 100644
--- a/Source/bindings/tests/results/core/V8TestInterface3.cpp
+++ b/Source/bindings/tests/results/core/V8TestInterface3.cpp
@@ -325,6 +325,8 @@ static void installV8TestInterface3Template(v8::Local<v8::FunctionTemplate> func
         V8DOMConfiguration::installMethod(isolate, prototypeTemplate, defaultSignature, v8::None, forEachMethodConfiguration);
     }
 
+    prototypeTemplate->Set(v8::Symbol::GetToStringTag(isolate), v8AtomicString(isolate, "TestInterface3"));
+
     // Custom toString template
     functionTemplate->Set(v8AtomicString(isolate, "toString"), V8PerIsolateData::from(isolate)->toStringTemplate());
 }