Remove spurious print that was causing test failures.

sky/sdk/lib/widgets/widget.dart

Index: sky/sdk/lib/widgets/widget.dart
diff --git a/sky/sdk/lib/widgets/widget.dart b/sky/sdk/lib/widgets/widget.dart
index 11fb763a7db1f1986c907bfe9a7fb4ae705b54b5..1154d73a1f2a9c48fc38f8f5a1c26215179edf47 100644
--- a/sky/sdk/lib/widgets/widget.dart
+++ b/sky/sdk/lib/widgets/widget.dart
@@ -503,8 +503,6 @@ abstract class RenderObjectWrapper extends Widget {
       _ancestor = findAncestor(RenderObjectWrapper);
       if (_ancestor is RenderObjectWrapper)
         _ancestor.insert(this, slot);
-      else
-        print("$this has no ancestor");
     } else {
       _root = old.root;
       _ancestor = old._ancestor;