Switch analyzer_cli to 'package:test'.

pkg/analyzer_cli/test/driver_test.dart

Index: pkg/analyzer_cli/test/driver_test.dart
diff --git a/pkg/analyzer_cli/test/driver_test.dart b/pkg/analyzer_cli/test/driver_test.dart
index cacbc2810b8e7a0771624a1e48596df883bbf050..0a41705490760b8a763b1fe69f06fcce9420c3c4 100644
--- a/pkg/analyzer_cli/test/driver_test.dart
+++ b/pkg/analyzer_cli/test/driver_test.dart
@@ -19,7 +19,7 @@ import 'package:analyzer_cli/src/driver.dart';
 import 'package:analyzer_cli/src/options.dart';
 import 'package:path/path.dart' as path;
 import 'package:plugin/plugin.dart';
-import 'package:unittest/unittest.dart';
+import 'package:test/test.dart';
 import 'package:yaml/src/yaml_node.dart';
 
 import 'utils.dart';
@@ -52,8 +52,6 @@ main() {
 
   tearDown(() => _tearDown());
 
-  initializeTestEnvironment();
-
   group('Driver', () {
     group('options', () {
       test('custom processor', () {