Use --use-cps-ir compiler option in the test script to run dart2js with the new backend.

tools/testing/dart/test_suite.dart

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 /**
  * Classes and methods for enumerating and preparing tests.
  *
  * This library includes:
  *
  * - Creating tests by listing all the Dart files in certain directories,
@@ skipping 2204 matching lines @@
         args.add("--categories=all");
       }
     }
     if ((compiler == "dart2js" || compiler == "dart2dart") &&
         configuration["minified"]) {
       args.add("--minify");
     }
     if (compiler == "dart2js" && configuration["csp"]) {
       args.add("--csp");
     }
+    if (compiler == "dart2js" && configuration["cps_ir"]) {
+      args.add("--use-cps-ir");
+    }
     if (compiler == "dartanalyzer" || compiler == "dart2analyzer") {
       args.add("--show-package-warnings");
       args.add("--enable-async");
     }
     return args;
   }
 
   static bool isBrowserRuntime(String runtime) {
     const BROWSERS = const [
       'drt',
@@ skipping 160 matching lines @@
       for (var key in PATH_REPLACEMENTS.keys) {
         if (path.startsWith(key)) {
           path = path.replaceFirst(key, PATH_REPLACEMENTS[key]);
           break;
         }
       }
     }
     return path;
   }
 }