This is needed because the Record.empty constant isn't implemented
yet, to avoid compile-time errors in tests that don't expect any.
Change-Id: Ic7e61fb285a65a5809979e4c32b632f73f9e2d88
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/260107
Reviewed-by: Erik Ernst <eernst@google.com>
Reviewed-by: Bob Nystrom <rnystrom@google.com>
Commit-Queue: Chloe Stefantsova <cstefantsova@google.com>
