Make TypeAccumulators follow LazyRefs

TypeMaps do the same, so it is logical, and helps
prevent subtle errors as when we mispredicted whether
a RecType contains references that point to it.

Also, add normalizeHkApply to homogenize

Fixes some discrepancies in Tasty typing.

Also, homogenize skolem types

Skolem types are eliminated by pickling, so they should not appear
in the "before-pickling" output.

Author: odersky

src/dotty/tools/dotc/core/Types.scala

@@ -3708,6 +3708,9 @@ object Types {
       case tp: JavaArrayType =>
         this(x, tp.elemType)
 
+      case tp: LazyRef =>
+        this(x, tp.ref)
+
       case tp: ProtoType =>
         tp.fold(x, this)
 

src/dotty/tools/dotc/printing/PlainPrinter.scala

@@ -53,6 +53,10 @@ class PlainPrinter(_ctx: Context) extends Printer {
         case tp @ TypeRef(_, tpnme.hkApplyOBS) =>
           val tp1 = tp.reduceProjection
           if (tp1 eq tp) tp else homogenize(tp1)
+        case tp: RefinedType =>
+          tp.normalizeHkApply
+        case tp: SkolemType =>
+          homogenize(tp.info)
         case tp: LazyRef =>
           homogenize(tp.ref)
         case _ =>