Remove some hacks in the testing scripts & prepare for checked mode handling with kernel

tools/testing/dart/test_runner.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 executing tests.
  *
  * This module includes:
  * - Managing parallel execution of tests, including timeout checks.
  * - Evaluating the output of each test as pass/fail/crash/timeout.
@@ skipping 2715 matching lines @@
     steps.add(() => device.runAdbCommand(
         ['push', processTest, '$devicedir/process_test']));
     steps.add(() => device.runAdbShellCommand(
         ['chmod', '777', '$devicedir/dart_precompiled_runtime $devicedir/process_test']));
 
     for (var file in files) {
       steps.add(() => device
           .runAdbCommand(['push', '$testdir/$file', '$deviceTestDir/$file']));
     }
 
-    var args = new List();
-    args.addAll(arguments);
-    for (var i = 0; i < args.length; i++) {
-      if (args[i].endsWith(".dart")) {
-        args[i] = "$deviceTestDir/out.aotsnapshot";
-      }
-    }
-
     steps.add(() => device.runAdbShellCommand(
         [
           '$devicedir/dart_precompiled_runtime',
-        ]..addAll(args),
+        ]..addAll(arguments),
         timeout: timeoutDuration));
 
     var stopwatch = new Stopwatch()..start();
     var writer = new StringBuffer();
 
     await device.waitForBootCompleted();
     await device.waitForDevice();
 
     AdbCommandResult result;
     for (var i = 0; i < steps.length; i++) {
@@ skipping 461 matching lines @@
     }
   }
 
   void eventAllTestsDone() {
     for (var listener in _eventListener) {
       listener.allDone();
     }
     _allDone();
   }
 }