Make .prototype properties of Wasm constructors read-only

src/wasm/wasm-js.cc

Index: src/wasm/wasm-js.cc
diff --git a/src/wasm/wasm-js.cc b/src/wasm/wasm-js.cc
index c6f72f67d16486d823c9c9128d512586b386fa22..182ea0f6b9f68f0b112b4bfcd13db578baf1533e 100644
--- a/src/wasm/wasm-js.cc
+++ b/src/wasm/wasm-js.cc
@@ -566,8 +566,9 @@ void WebAssemblyMemoryGetBuffer(
 static i::Handle<i::FunctionTemplateInfo> NewTemplate(i::Isolate* i_isolate,
                                                       FunctionCallback func) {
   Isolate* isolate = reinterpret_cast<Isolate*>(i_isolate);
-  Local<FunctionTemplate> local = FunctionTemplate::New(isolate, func);
-  return v8::Utils::OpenHandle(*local);
+  Local<FunctionTemplate> templ = FunctionTemplate::New(isolate, func);
+  templ->ReadOnlyPrototype();
+  return v8::Utils::OpenHandle(*templ);
 }
 
 namespace internal {