Extract testing utilities into a separate package.

pkg/analysis_server/test/computer/element_test.dart

 // Copyright (c) 2014, 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.computer.element;
 
 import 'package:analysis_server/src/computer/element.dart';
 import 'package:analysis_server/src/constants.dart';
+import 'package:analysis_testing/abstract_context.dart';
+import 'package:analysis_testing/reflective_tests.dart';
 import 'package:analyzer/src/generated/ast.dart';
 import 'package:analyzer/src/generated/element.dart' as engine;
 import 'package:analyzer/src/generated/source.dart';
 import 'package:analyzer/src/generated/utilities_dart.dart' as engine;
 import 'package:unittest/unittest.dart';
 
-import '../abstract_context.dart';
-import '../reflective_tests.dart';
 
 
 main() {
   groupSep = ' | ';
   group('Element', () {
     runReflectiveTests(ElementTest);
   });
   group('ElementKind', () {
     runReflectiveTests(ElementKindTest);
   });
@@ skipping 242 matching lines @@
       },
       FLAGS: Element.FLAG_DEPRECATED | Element.FLAG_PRIVATE |
           Element.FLAG_STATIC,
       PARAMETERS: '(int a, String b)',
       RETURN_TYPE: 'List<String>'
     };
     Element element = new Element.fromJson(json);
     expect(element.toJson(), equals(json));
   }
 }