test data.equals with empty

Change-Id: Ib79fb2ba099a0d094ab16b1d7307c03e64b1fd1f
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/271240
Commit-Queue: Mike Reed <reed@google.com>
Auto-Submit: Mike Reed <reed@google.com>
Reviewed-by: Ben Wagner <bungeman@google.com>
4 files changed