unittest step2: bye bye to multiple entrypoints for unittest

lib/unittest/unittest_vm.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.
-
-/**
- * A simple unit test library for running tests on the VM.
- */
-#library('unittest');
-
-#import('dart:io');
-#import('dart:isolate');
-
-#source('config.dart');
-#source('shared.dart');
-
-class PlatformConfiguration extends Configuration {
-  void onDone(int passed, int failed, int errors, List<TestCase> results) {
-    try {
-      super.onDone(passed, failed, errors, results);
-    } catch (Exception ex) {
-      // A non-zero exit code is used by the test infrastructure to detect
-      // failure.
-      exit(1);
-    }
-  }
-}