Bugfixes in CPS RecursiveVisitor and ParentVisitor.

pkg/compiler/lib/src/cps_ir/shrinking_reductions.dart

Index: pkg/compiler/lib/src/cps_ir/shrinking_reductions.dart
diff --git a/pkg/compiler/lib/src/cps_ir/shrinking_reductions.dart b/pkg/compiler/lib/src/cps_ir/shrinking_reductions.dart
index 79234f847cbf57547006aaf96519b5210685a7ce..199d2d6f48c99bd33ca9b0bfa1fc8850faa9c317 100644
--- a/pkg/compiler/lib/src/cps_ir/shrinking_reductions.dart
+++ b/pkg/compiler/lib/src/cps_ir/shrinking_reductions.dart
@@ -509,12 +509,11 @@ class ParentVisitor extends RecursiveVisitor {
   // Expressions.
 
   processFieldInitializer(FieldInitializer node) {
-    node.body.body.parent = node;
+    node.body.parent = node;
   }
 
   processSuperInitializer(SuperInitializer node) {
-    node.arguments.forEach(
-        (RunnableBody argument) => argument.body.parent = node);
+    node.arguments.forEach((RunnableBody argument) => argument.parent = node);
   }
 
   processLetPrim(LetPrim node) {