Remove deprecated code

pkg/analyzer_cli/test/sdk_ext_test.dart

Index: pkg/analyzer_cli/test/sdk_ext_test.dart
diff --git a/pkg/analyzer_cli/test/sdk_ext_test.dart b/pkg/analyzer_cli/test/sdk_ext_test.dart
index 6aa793dc18fea7c2a95eb716ce2797d05c4a08b2..e7aa5ce954835046c305711905308f85a71e9daf 100644
--- a/pkg/analyzer_cli/test/sdk_ext_test.dart
+++ b/pkg/analyzer_cli/test/sdk_ext_test.dart
@@ -2,7 +2,6 @@
 // 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.
 
-
 /// Test that sdk extensions are properly detected in various scenarios.
 library analyzer_cli.test.sdk_ext;
 
@@ -17,7 +16,7 @@ import 'utils.dart';
 // TODO(pq): fix tests to run safely on the bots
 // https://github.com/dart-lang/sdk/issues/25001
 main() {}
-_main() {
+not_main() {
   group('Sdk extensions', () {
     StringSink savedOutSink, savedErrorSink;
     int savedExitCode;