node-api: fix crash in finalization

Refs: nodejs/node-addon-api#906
Refs: #37616

Fix crash introduced by #37616

Signed-off-by: Michael Dawson <mdawson@devrus.com>

PR-URL: #37876
Backport-PR-URL: #42512
Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Rich Trott <rtrott@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>

Author: mhdawson

Diff for: src/js_native_api_v8.cc

@@ -373,8 +373,11 @@ class Reference : public RefBase {
   inline void Finalize(bool is_env_teardown = false) override {
     // During env teardown, `~napi_env()` alone is responsible for finalizing.
     // Thus, we don't want any stray gc passes to trigger a second call to
-    // `Finalize()`, so let's reset the persistent here.
-    if (is_env_teardown) _persistent.ClearWeak();
+    // `Finalize()`, so let's reset the persistent here if nothing is
+    // keeping it alive.
+    if (is_env_teardown && _persistent.IsWeak()) {
+      _persistent.ClearWeak();
+    }
 
     // Chain up to perform the rest of the finalization.
     RefBase::Finalize(is_env_teardown);