dart2js cps: Type casts and related changes to type propagation.

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 ea14f3c948dcce15ea2163b7cea4f4ab3b59b3df..0a5dbe7d1f16160f0ba222446470272dae18a811 100644
--- a/pkg/compiler/lib/src/cps_ir/shrinking_reductions.dart
+++ b/pkg/compiler/lib/src/cps_ir/shrinking_reductions.dart
@@ -562,12 +562,17 @@ class ParentVisitor extends RecursiveVisitor {
     node.falseContinuation.parent = node;
   }
 
-  processTypeOperator(TypeOperator node) {
+  processTypeCast(TypeCast node) {
     node.typeArguments.forEach((Reference ref) => ref.parent = node);
     node.continuation.parent = node;
     node.value.parent = node;
   }
 
+  processTypeTest(TypeTest node) {
+    node.typeArguments.forEach((Reference ref) => ref.parent = node);
+    node.value.parent = node;
+  }
+
   processSetMutableVariable(SetMutableVariable node) {
     node.variable.parent = node;
     node.body.parent = node;