dart2js cps_ir: Use interceptors for is-checks.

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

Index: pkg/compiler/lib/src/cps_ir/cps_ir_nodes_sexpr.dart
diff --git a/pkg/compiler/lib/src/cps_ir/cps_ir_nodes_sexpr.dart b/pkg/compiler/lib/src/cps_ir/cps_ir_nodes_sexpr.dart
index 3fd8503e585d248dbc1a834d7ac3356571fde2c8..f82014cfd9f5feaf9594ff286a70627d166b10bb 100644
--- a/pkg/compiler/lib/src/cps_ir/cps_ir_nodes_sexpr.dart
+++ b/pkg/compiler/lib/src/cps_ir/cps_ir_nodes_sexpr.dart
@@ -246,6 +246,14 @@ class SExpressionStringifier extends Indentation implements Visitor<String> {
     return '(TypeTest $value ${node.dartType} ($typeArguments))';
   }
 
+  String visitTypeTestRaw(TypeTestRaw node) {
+    String value = access(node.value);
+    String interceptor = node.interceptor == null
+        ? ''
+        : ' ${access(node.interceptor)}';
+    return '(TypeTestRaw $value ${node.dartType} ()$interceptor)';
+  }
+
   String visitLiteralList(LiteralList node) {
     String values = node.values.map(access).join(' ');
     return '(LiteralList ($values))';