src: remove superfluous HandleScope

Accessors implicitly run inside a HandleScope, UDPWrap::GetFD() doesn't
need to create one explicitly.

PR-URL: nodejs/node#16482
Reviewed-By: Franziska Hinkelmann <franziska.hinkelmann@gmail.com>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Tobias Nießen <tniessen@tnie.de>
Reviewed-By: Anna Henningsen <anna@addaleax.net>

src/udp_wrap.cc

@@ -169,7 +169,6 @@ void UDPWrap::New(const FunctionCallbackInfo<Value>& args) {
 void UDPWrap::GetFD(Local<String>, const PropertyCallbackInfo<Value>& args) {
   int fd = UV_EBADF;
 #if !defined(_WIN32)
-  HandleScope scope(args.GetIsolate());
   UDPWrap* wrap = Unwrap<UDPWrap>(args.Holder());
   if (wrap != nullptr)
     uv_fileno(reinterpret_cast<uv_handle_t*>(&wrap->handle_), &fd);