The added tests exhibit forwarding stubs injected into mixin
application classes. These are currently not handled fully or
consistently throughout the CFE and can lead to crashes and errors.
Change-Id: Ib6a14c6adc48daa35f4a3a8e5b705ec3cf7f606d
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/168652
Reviewed-by: Jens Johansen <jensj@google.com>
Commit-Queue: Johnni Winther <johnniwinther@google.com>