Switch analysis_server to use 'package:test'.

pkg/analysis_server/test/edit/format_test.dart

Index: pkg/analysis_server/test/edit/format_test.dart
diff --git a/pkg/analysis_server/test/edit/format_test.dart b/pkg/analysis_server/test/edit/format_test.dart
index d864ef9d546442bbb7fb40692d4958bddac89c33..71c54fcffef998d41a4c265b696e8a2f32cd7cd8 100644
--- a/pkg/analysis_server/test/edit/format_test.dart
+++ b/pkg/analysis_server/test/edit/format_test.dart
@@ -9,8 +9,8 @@ import 'dart:async';
 import 'package:analysis_server/plugin/protocol/protocol.dart';
 import 'package:analysis_server/src/edit/edit_domain.dart';
 import 'package:plugin/manager.dart';
+import 'package:test/test.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
-import 'package:unittest/unittest.dart' hide ERROR;
 
 import '../analysis_abstract.dart';
 import '../mocks.dart';
@@ -18,7 +18,9 @@ import '../utils.dart';
 
 main() {
   initializeTestEnvironment();
-  defineReflectiveTests(FormatTest);
+  defineReflectiveSuite(() {
+    defineReflectiveTests(FormatTest);
+  });
 }
 
 @reflectiveTest