src: create a HandleScope in FinalizeCallback

Refs: nodejs/node-addon-api#832

Seems like FinalizeCallback needs to create a HandleScope
since it calls ObjectWrap::~ObjectWrap() which might need
to create a temporary Object handle here
https://github.com/nodejs/node-addon-api/blob/master/napi-inl.h#L3558

at Realm (https://github.com/realm/realm-js) we have crashes
with stacktrace at this location.

While fixed in core for later versions we still need for
older versions of Node.js

PR-URL: nodejs/node-addon-api#832
Reviewed-By: Gabriel Schulhof <gabriel.schulhof@intel.com>
Reviewed-By: Kevin Eady <kevin.c.eady@gmail.com>
Reviewed-By: Michael Dawson <midawson@redhat.com>
Reviewed-By: NickNaso <nicoladelgobbo@gmail.com>

napi-inl.h

@@ -3977,6 +3977,7 @@ inline napi_value ObjectWrap<T>::StaticSetterCallbackWrapper(
 
 template <typename T>
 inline void ObjectWrap<T>::FinalizeCallback(napi_env env, void* data, void* /*hint*/) {
+  HandleScope scope(env);
   T* instance = static_cast<T*>(data);
   instance->Finalize(Napi::Env(env));
   delete instance;