refactor(testScheduler-ui): fix the exception augmentation for tests …

…to clone the exception

spec/helpers/testScheduler-ui.ts

@@ -109,7 +109,7 @@ module.exports = function(suite) {
  if (notification) {
  const { kind, exception } = notification;
  if (kind === 'E' && exception instanceof Error) {
- exception.stack = null;
+ notification.exception = { name: exception.name, message: exception.message };
  }
  }
  return marble;