I didn't adjust this when removing nnbd_migration in https://dart-review.googlesource.com/c/sdk/+/340160.

Change-Id: I21829c3052be1671a2407f219a332a7a62197ce5
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/340361


Reviewed-by: Alexander Thomas <athom@google.com>
Auto-Submit: Parker Lougheed <parlough@gmail.com>
Commit-Queue: Alexander Thomas <athom@google.com>
Reviewed-by: Samuel Rawlins <srawlins@google.com>