fix Kan for 2.9.3

Compile error:

Kan.scala:105: private value xp escapes its defining scope as part of
type H[(this.xfp.I, this.xp.I)]
optimize IList#scanLeft, scanRight
resize sequentialFusion and sequentialFusion1 Prop

sometimes `sequentialFusion` and `sequentialFusion1` generate too large objects.
it cause OutOfMemoryError or test hang on travis-ci