SI-7643 WIP enable newPatternMatching in interactive.

Without it, the enclosed test fails with:

    ArrayBuffer(Problem(RangePosition(partial-fun/src/PartialFun.scala, 62, 62, 77),type mismatch;
     found   : Int => Int
     required: PartialFunction[Int,Int],2))

This commit quickly flips the switch to discover what counter
forces are at play.

Review by build kitteh.