Fix pickling/unpickling of names

Running the test suite with the pickling printer on showed up two more
problems which are fixed in this commit.

Author: odersky

compiler/src/dotty/tools/dotc/core/NameKinds.scala

@@ -141,6 +141,13 @@ object NameKinds {
     }
   }
 
+  object AnyNumberedName {
+    def unapply(name: DerivedTermName): Option[(TermName, Int)] = name match {
+      case DerivedTermName(qual, info: NumberedInfo) => Some((qual, info.num))
+      case _ => None
+    }
+  }
+
   case class UniqueNameKind(val separator: String)
   extends NumberedNameKind(UNIQUE, s"Unique $separator") {
     override def definesNewName = true

compiler/src/dotty/tools/dotc/core/tasty/NameBuffer.scala

@@ -45,7 +45,7 @@ class NameBuffer extends TastyBuffer(10000) {
     val lengthAddr = currentAddr
     for (i <- 0 until lengthWidth) writeByte(0)
     op
-    val length = currentAddr.index - lengthAddr.index - 1
+    val length = currentAddr.index - lengthAddr.index - lengthWidth
     putNat(lengthAddr, length, lengthWidth)
   }
 
@@ -70,10 +70,10 @@ class NameBuffer extends TastyBuffer(10000) {
           writeNat(num)
           if (!original.isEmpty) writeNameRef(original)
         }
-      case DefaultGetterName(method, paramNumber) =>
-        withLength { writeNameRef(method); writeNat(paramNumber) }
       case VariantName(original, sign) =>
         withLength { writeNameRef(original); writeNat(sign + 1) }
+      case AnyNumberedName(original, num) =>
+        withLength { writeNameRef(original); writeNat(num) }
       case SignedName(original, Signature(params, result)) =>
         withLength(
           { writeNameRef(original); writeNameRef(result); params.foreach(writeNameRef) },

compiler/src/dotty/tools/dotc/core/tasty/TastyUnpickler.scala

@@ -61,6 +61,8 @@ class TastyUnpickler(reader: TastyReader) {
         DefaultGetterName(readName(), readNat())
       case VARIANT =>
         VariantName(readName(), readNat() - 1)
+      case OUTERSELECT =>
+        OuterSelectName(readName(), readNat())
       case SIGNED =>
         val original = readName()
         val result = readName().toTypeName