Deprecate the generated AST library and clean up imports

pkg/analysis_server/test/services/refactoring/rename_import_test.dart

 // Copyright (c) 2014, the Dart project authors.  Please see the AUTHORS file
 // 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.
 
 library test.services.refactoring.rename_import;
 
 import 'package:analysis_server/plugin/protocol/protocol.dart';
-import 'package:analyzer/src/generated/ast.dart';
+import 'package:analyzer/dart/ast/ast.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
 import 'package:unittest/unittest.dart';
 
 import '../../utils.dart';
 import 'abstract_rename.dart';
 
 main() {
   initializeTestEnvironment();
   defineReflectiveTests(RenameImportTest);
 }
@@ skipping 204 matching lines @@
     expect(refactoring.refactoringName, 'Rename Import Prefix');
     expect(refactoring.oldName, '');
   }
 
   void _createRefactoring(String search) {
     ImportDirective directive =
         findNodeAtString(search, (node) => node is ImportDirective);
     createRenameRefactoringForElement(directive.element);
   }
 }