Switch analysis_server to use 'package:test'.

pkg/analysis_server/test/operation/operation_queue_test.dart

Index: pkg/analysis_server/test/operation/operation_queue_test.dart
diff --git a/pkg/analysis_server/test/operation/operation_queue_test.dart b/pkg/analysis_server/test/operation/operation_queue_test.dart
index e6926c91d52fc39c0a38a0d254e161c5a688754f..4d98e63604c954761446250c5fd14921827337cf 100644
--- a/pkg/analysis_server/test/operation/operation_queue_test.dart
+++ b/pkg/analysis_server/test/operation/operation_queue_test.dart
@@ -13,16 +13,18 @@ import 'package:analysis_server/src/services/search/search_engine.dart';
 import 'package:analyzer/file_system/file_system.dart';
 import 'package:analyzer/src/generated/engine.dart';
 import 'package:analyzer/src/generated/source.dart';
+import 'package:test/test.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
 import 'package:typed_mock/typed_mock.dart';
-import 'package:unittest/unittest.dart';
 
 import '../mocks.dart';
 import '../utils.dart';
 
 main() {
   initializeTestEnvironment();
-  defineReflectiveTests(ServerOperationQueueTest);
+  defineReflectiveSuite(() {
+    defineReflectiveTests(ServerOperationQueueTest);
+  });
 }
 
 /**