Fix tests and bootstrapped code

There were two occurrences where we exploited that a case class with a private
constructor still had a public apply method. I believe both were mistakes.

Author: odersky

compiler/src/dotty/tools/dotc/interactive/Interactive.scala

@@ -22,7 +22,7 @@ object Interactive {
   import ast.tpd._
 
   object Include {
-    case class Set private (val bits: Int) extends AnyVal {
+    case class Set private[Include] (val bits: Int) extends AnyVal {
       def | (that: Set): Set = Set(bits | that.bits)
       def except(that: Set): Set = Set(bits & ~that.bits)
 

tests/pos/i4564.scala

@@ -51,7 +51,7 @@ class BaseNCP[T] {
 }
 
 object NoClashPoly extends BaseNCP[Boolean]
-case class NoClashPoly private(x: Int)
+case class NoClashPoly (x: Int)
 
 
 class BaseCP[T] {