src: simplify native immediate by using v8::Global

Unlike `node::Persistent`, `v8::Global` has move semantics and can be used directly in STL containers. PR-URL: #26254 Reviewed-By: Gus Caplan <me@gus.host> Reviewed-By: Colin Ihrig <cjihrig@gmail.com> Reviewed-By: Ben Noordhuis <info@bnoordhuis.nl> Reviewed-By: Joyee Cheung <joyeec9h3@gmail.com> Reviewed-By: James M Snell <jasnell@gmail.com>

Author: addaleax

src/env-inl.h

@@ -590,8 +590,7 @@ void Environment::CreateImmediate(native_immediate_callback cb,
  native_immediate_callbacks_.push_back({
  cb,
  data,
- std::unique_ptr<Persistent<v8::Object>>(obj.IsEmpty() ?
- nullptr : new Persistent<v8::Object>(isolate_, obj)),
+ v8::Global<v8::Object>(isolate_, obj),
  ref
  });
  immediate_info()->count_inc(1);

src/env.h

@@ -977,7 +977,7 @@ class Environment {
  struct NativeImmediateCallback {
  native_immediate_callback cb_;
  void* data_;
- std::unique_ptr<Persistent<v8::Object>> keep_alive_;
+ v8::Global<v8::Object> keep_alive_;
  bool refed_;
  };
  std::vector<NativeImmediateCallback> native_immediate_callbacks_;