src: avoid duplicate AtExit functions

node.cc had two functions with the name AtExit with entirely different
purposes:

* node::AtExit(): file static; used to register the atexit(3) handler
  for the Node process.
* node::AtExit(void (*)(void*), void*): publicly exported symbol that
  addons can use to request callbacks upon exit.

For code readability it is better to avoid the unintentional overload.

PR-URL: #8273
Reviewed-By: addaleax - Anna Henningsen <anna@addaleax.net>
Reviewed-By: jasnell - James M Snell <jasnell@gmail.com>
Reviewed-By: cjihrig - Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: bnoordhuis - Ben Noordhuis <info@bnoordhuis.nl>

src/node.cc

@@ -3406,7 +3406,7 @@ void SetupProcessObject(Environment* env,
 #undef READONLY_PROPERTY
 
 
-static void AtExit() {
+static void AtProcessExit() {
   uv_tty_reset_mode();
 }
 
@@ -3443,7 +3443,7 @@ void LoadEnvironment(Environment* env) {
   env->isolate()->SetFatalErrorHandler(node::OnFatalError);
   env->isolate()->AddMessageListener(OnMessage);
 
-  atexit(AtExit);
+  atexit(AtProcessExit);
 
   TryCatch try_catch(env->isolate());