Switch analysis_server to use 'package:test'.

pkg/analysis_server/test/integration/completion/test_all.dart

Index: pkg/analysis_server/test/integration/completion/test_all.dart
diff --git a/pkg/analysis_server/test/integration/completion/test_all.dart b/pkg/analysis_server/test/integration/completion/test_all.dart
index aae07f3ecd621c993bf21affa45f131d1e81bca9..89b28f4b732ab15acb4120c8e84d3588da7d1da0 100644
--- a/pkg/analysis_server/test/integration/completion/test_all.dart
+++ b/pkg/analysis_server/test/integration/completion/test_all.dart
@@ -4,7 +4,7 @@
 
 library test.integration.completion.all;
 
-import 'package:unittest/unittest.dart';
+import 'package:test_reflective_loader/test_reflective_loader.dart';
 
 import '../../utils.dart';
 import 'get_suggestions_test.dart' as get_suggestions_test;
@@ -14,7 +14,7 @@ import 'get_suggestions_test.dart' as get_suggestions_test;
  */
 main() {
   initializeTestEnvironment();
-  group('completion', () {
+  defineReflectiveSuite(() {
     get_suggestions_test.main();
-  });
+  }, name: 'completion');
 }