Reorganize tests

Author: liufengyun

tests/init/neg/features-doublelist.scala renamed to tests/init/pos/features-doublelist.scala

@@ -1,6 +1,6 @@
 class DoubleList {
   class Node(var prev: Node, var next: Node, data: Int)
-  object sentinel extends Node(sentinel, sentinel, 0)  // error // error
+  object sentinel extends Node(sentinel, sentinel, 0)
 
   def insert(x: Int) = ???
 }

tests/init/neg/lazylist1.scala renamed to tests/init/pos/lazylist1.scala

@@ -2,7 +2,7 @@ class LazyList[A]
 
 object LazyList {
   inline implicit def toDeferred[A](l: LazyList[A]): Deferred[A] =
-    new Deferred(l)  // error
+    new Deferred(l)
 
   final class Deferred[A](l: => LazyList[A]) {
     def #:: [B >: A](elem: => B): LazyList[B] = ???