Refactor unittests

tests/compiler/dart2js/exit_code_test.dart

 // Copyright (c) 2013, 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.
 
 // Test the exit code of dart2js in case of exceptions, errors, warnings, etc.
 
 
 import 'dart:async';
 import 'dart:io' show Platform;
 
@@ skipping 224 matching lines @@
     void exit(exitCode) {
       if (foundExitCode == null) {
         foundExitCode = exitCode;
       }
     };
 
     entry.exitFunc = exit;
     entry.compileFunc = compile;
 
     List<String> args = new List<String>.from(options)
-        ..add("tests/compiler/dart2js/exit_code_helper.dart");
+        ..add("tests/compiler/dart2js/data/exit_code_helper.dart");
     Future result = entry.internalMain(args);
     return result.catchError((e, s) {
       // Capture crashes.
     }).whenComplete(checkResult);
   });
 }
 
 Future testExitCodes(
     String marker, Map<String,int> expectedExitCodes, List<String> options) {
   return Future.forEach(expectedExitCodes.keys, (String type) {
@@ skipping 50 matching lines @@
 
       expected = _expectedExitCode(
           beforeRun: tests[marker], fatalWarnings: true);
       totalExpectedErrors += expected.length;
       await testExitCodes(marker, expected, ['--fatal-warnings']);
     }
 
     Expect.equals(totalExpectedErrors, checkedResults);
   });
 }