dart2js cps: Tolerate refinements in more cases.

pkg/compiler/lib/src/js_backend/codegen/task.dart

Index: pkg/compiler/lib/src/js_backend/codegen/task.dart
diff --git a/pkg/compiler/lib/src/js_backend/codegen/task.dart b/pkg/compiler/lib/src/js_backend/codegen/task.dart
index f6a8f101a5ad10d10d16599b402324c71a96d60b..754313178158ea281d97becce3dfbab721f0c9ad 100644
--- a/pkg/compiler/lib/src/js_backend/codegen/task.dart
+++ b/pkg/compiler/lib/src/js_backend/codegen/task.dart
@@ -237,6 +237,7 @@ class CpsFunctionCompiler implements FunctionCompiler {
       applyCpsPass(new MutableVariableEliminator(), cpsFunction);
       applyCpsPass(new RedundantJoinEliminator(), cpsFunction);
       applyCpsPass(new RedundantPhiEliminator(), cpsFunction);
+      applyCpsPass(new UpdateRefinements(typeSystem), cpsFunction);
       applyCpsPass(new ShrinkingReducer(), cpsFunction);
       applyCpsPass(new OptimizeInterceptors(backend, typeSystem), cpsFunction);
       applyCpsPass(new BackwardNullCheckRemover(typeSystem), cpsFunction);