Switch analysis_server to use 'package:test'.

pkg/analysis_server/test/search/element_references_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.search.element_references;
 
 import 'dart:async';
 
 import 'package:analysis_server/plugin/protocol/protocol.dart';
 import 'package:analysis_server/src/services/index/index.dart';
+import 'package:test/test.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
-import 'package:unittest/unittest.dart';
 
 import '../utils.dart';
 import 'abstract_search_domain.dart';
 
 main() {
   initializeTestEnvironment();
-  defineReflectiveTests(ElementReferencesTest);
-  defineReflectiveTests(_NoSearchEngine);
+  defineReflectiveSuite(() {
+    defineReflectiveTests(ElementReferencesTest);
+    defineReflectiveTests(_NoSearchEngine);
+  });
 }
 
 @reflectiveTest
 class ElementReferencesTest extends AbstractSearchDomainTest {
   Element searchElement;
 
   void assertHasRef(SearchResultKind kind, String search, bool isPotential) {
     assertHasResult(kind, search);
     expect(result.isPotential, isPotential);
   }
@@ skipping 699 matching lines @@
   print(vvv);
 }
 ''');
     Request request = new SearchFindElementReferencesParams(testFile, 0, false)
         .toRequest('0');
     Response response = await waitResponse(request);
     expect(response.error, isNotNull);
     expect(response.error.code, RequestErrorCode.NO_INDEX_GENERATED);
   }
 }