Initial support to test.dart for running precompiler tests on android devices

tools/testing/dart/test_options.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.
 
 library test_options_parser;
 
 import "dart:io";
 import "drt_updater.dart";
 import "test_suite.dart";
 import "path.dart";
@@ skipping 139 matching lines @@
             'simarm64',
             'simmips',
             'simdbc',
             'simdbc64',
           ],
           'x64'),
       new _TestOptionSpecification(
           'system',
           'The operating system to run tests on',
           ['-s', '--system'],
-          ['linux', 'macos', 'windows'],
+          ['linux', 'macos', 'windows', 'android'],
           Platform.operatingSystem),
       new _TestOptionSpecification(
           'checked', 'Run tests in checked mode', ['--checked'], [], false,
           type: 'bool'),
       new _TestOptionSpecification('host_checked',
           'Run compiler in checked mode', ['--host-checked'], [], false,
           type: 'bool'),
       new _TestOptionSpecification('minified',
           'Enable minification in the compiler', ['--minified'], [], false,
           type: 'bool'),
@@ skipping 723 matching lines @@
       if (option.keys.contains(name)) {
         return option;
       }
     }
     print('Unknown test option $name');
     exit(1);
   }
 
   List<_TestOptionSpecification> _options;
 }