message: refactor: remove unnecessary else clause.
  Addresses comment: https://github.com/ReactiveX/rxjs/pull/5745/files/362b0493a7cb36e14d1e2a4bc77d8bcce3db47e1\#r493764091
diff: @@ -163,7 +163,6 @@ export class SafeSubscriber<T> extends Subscriber<T> {
  function handleError(err: any) {
  if (config.useDeprecatedSynchronousErrorHandling) {
  throw err;
  - } else {
  - reportUnhandledError(err);
  }
  + reportUnhandledError(err);
  }
  