src: use cached emit v8::String

Signed-off-by: Daeyeon Jeong <daeyeon.dev@gmail.com>
PR-URL: #57249
Reviewed-By: Michaël Zasso <targos@protonmail.com>
Reviewed-By: Jake Yuesong Li <jake.yuesong@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>

src/node_process_events.cc

@@ -56,7 +56,8 @@ MaybeLocal<Value> ProcessEmit(Environment* env,
 
   Local<Object> process = env->process_object();
   Local<Value> argv[] = {event_string, message};
-  return MakeCallback(isolate, process, "emit", arraysize(argv), argv, {0, 0});
+  return MakeCallback(
+      isolate, process, env->emit_string(), arraysize(argv), argv, {0, 0});
 }
 
 Maybe<bool> ProcessEmitWarningGeneric(Environment* env,