Migration: add a test case for #44118.
Migration: add a test case for #44118.

Bug: https://github.com/dart-lang/sdk/issues/44118
Change-Id: I9c62d8d90240458c8609a74a2cd49b703da0fb29
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/171240
Reviewed-by: Samuel Rawlins <5cf2cac5eec2ad6d0eb2b0f4ff6af9a590ce2bf6@google.com>
Commit-Queue: Paul Berry <72d414e3a99fb120308437779d51667bcc0984eb@google.com>

dart-lang/sdk,dart-lang/sdk,dart-lang/sdk,dart-lang/sdk,dart-lang/sdk,dart-lang/sdk,dart-lang/sdk,dart-lang/sdk