It uses the same logic as an old back-end
(see SamType#createByValueParameter and genericSamProjectedOut.kt),
split into two parts:
1. When inserting SAM casts, use SamType#createByValueParamerer to get
the target SAM type.
2. When inserting implicit casts, cast SAM conversions as arguments of
methods of out-projected types to the original type of value parameter
instead of 'Nothing'.
Dmitry Petrov