src: check for empty maybe local

Using ToLocalChecked on MaybeLocal without verifying it's empty
can lead to unattempted crash.

PR-URL: #32339
Reviewed-By: Michaël Zasso <targos@protonmail.com>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: David Carlier <devnexen@gmail.com>
Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: James M Snell <jasnell@gmail.com>

src/udp_wrap.cc

@@ -516,7 +516,8 @@ void UDPWrap::DoSend(const FunctionCallbackInfo<Value>& args, int family) {
 
   // construct uv_buf_t array
   for (size_t i = 0; i < count; i++) {
-    Local<Value> chunk = chunks->Get(env->context(), i).ToLocalChecked();
+    Local<Value> chunk;
+    if (!chunks->Get(env->context(), i).ToLocal(&chunk)) return;
 
     size_t length = Buffer::Length(chunk);