It wasn't waiting for anything, so it would consider the test done
before the expectation was even reached. Went ahead and migrated it to
the simpler expect and async_helper libraries in the process.
Change-Id: I1d498980f34985bc5d54c5a514711143c689c199
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/136080
Auto-Submit: Bob Nystrom <rnystrom@google.com>
Reviewed-by: Mayank Patke <fishythefish@google.com>
Robert Nystrom
2225d1895d