[benchmark] Test null safe options.
[benchmark] Test null safe options.

TBR=athom@google.com

Change-Id: Ic3ea7969ea486f646669e0cff6bb59385bc927c0
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/151843
Reviewed-by: Jonas Termansen <092ec58085ae5e368bc39d18752740ff81a2d09c@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