Remove cancel and make crash exit with code 253.

tests/compiler/dart2js/unparser2_test.dart

Index: tests/compiler/dart2js/unparser2_test.dart
diff --git a/tests/compiler/dart2js/unparser2_test.dart b/tests/compiler/dart2js/unparser2_test.dart
index 5129619228ed5f772c8dd3ea4d84ac8dd063a238..fa5f0bb3911fc6610ee696b2e8bf92975aebdf2b 100644
--- a/tests/compiler/dart2js/unparser2_test.dart
+++ b/tests/compiler/dart2js/unparser2_test.dart
@@ -75,19 +75,12 @@ class MessageCollector implements DiagnosticListener {
   MessageCollector() {
     messages = [];
   }
-  void cancel(String reason, {node, token, instruction, element}) {
+  void internalError(node, String reason) {
     messages.add(reason);
     throw reason;
   }
+
   void log(message) {
     messages.add(message);
   }
-  void internalErrorOnElement(Element element, String message) {
-    throw message;
-  }
-  void internalError(String message,
-                     {Node node, Token token, dynamic instruction,
-                      Element element}) {
-    throw message;
-  }
 }