src: move default assignment of async_id_ in async_wrap.h

Moving the default assignment of async_id from the constructor in
async_wrap.cc to class definition in async_wrap.h

PR-URL: #23495
Reviewed-By: Anna Henningsen <[email protected]>
Reviewed-By: Colin Ihrig <[email protected]>
Reviewed-By: Gireesh Punathil <[email protected]>
Reviewed-By: James M Snell <[email protected]>
Reviewed-By: Shelley Vohr <[email protected]>
Reviewed-By: Sakthipriyan Vairamani <[email protected]>
Reviewed-By: Trivikram Kamat <[email protected]>

src/async_wrap.h

@@ -201,7 +201,7 @@ class AsyncWrap : public BaseObject {
   inline AsyncWrap();
   const ProviderType provider_type_;
   // Because the values may be Reset(), cannot be made const.
-  double async_id_;
+  double async_id_ = -1;
   double trigger_async_id_;
 };