dart2js cps: Remove NonTailThrow.

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 c6cdfc57b946c925396e378192224e8adb4757c4..1a317c4d454f0aefa2259152ab4f52fd8c353c56 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
@@ -314,11 +314,6 @@ class SExpressionStringifier extends Indentation implements Visitor<String> {
     return '(TypeExpression ${node.dartType} ($args))';
   }
 
-  String visitNonTailThrow(NonTailThrow node) {
-    String value = access(node.value);
-    return '(NonTailThrow $value)';
-  }
-
   String visitCreateInvocationMirror(CreateInvocationMirror node) {
     String selector = node.selector.name;
     String args = node.arguments.map(access).join(' ');