napi: supress invalid coverity leak message

Coverity was complaining that finalizer was being
leaked in this method, however it should be
freed when the buffer is finalized so I believe
the message is invalid.

Add the required comments to suppress the warning.

PR-URL: https://github.com/nodejs/node/pull/12192
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Ben Noordhuis <info@bnoordhuis.nl>
Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: Hitesh Kanwathirtha <hiteshk@microsoft.com>

src/node_api.cc

@@ -2290,6 +2290,10 @@ napi_status napi_create_external_buffer(napi_env env,
 
   *result = v8impl::JsValueFromV8LocalValue(maybe.ToLocalChecked());
   return GET_RETURN_STATUS();
+  // Tell coverity that 'finalizer' should not be freed when we return
+  // as it will be deleted when the buffer to which it is associated
+  // is finalized.
+  // coverity[leaked_storage]
 }
 
 napi_status napi_create_buffer_copy(napi_env env,