Deprecate the generated AST library and clean up imports

pkg/analysis_server/test/plugin/protocol_dart_test.dart

Index: pkg/analysis_server/test/plugin/protocol_dart_test.dart
diff --git a/pkg/analysis_server/test/plugin/protocol_dart_test.dart b/pkg/analysis_server/test/plugin/protocol_dart_test.dart
index 2d0edddebb657d15d5b519313147a54d1b0c4c86..8920e92078fa10a2687235b7f7fa4044dfe1564b 100644
--- a/pkg/analysis_server/test/plugin/protocol_dart_test.dart
+++ b/pkg/analysis_server/test/plugin/protocol_dart_test.dart
@@ -6,10 +6,12 @@ library test.computer.element;
 
 import 'package:analysis_server/plugin/protocol/protocol.dart';
 import 'package:analysis_server/plugin/protocol/protocol_dart.dart';
+import 'package:analyzer/dart/ast/ast.dart' as engine;
+import 'package:analyzer/dart/ast/visitor.dart' as engine;
 import 'package:analyzer/dart/element/element.dart' as engine;
 import 'package:analyzer/dart/element/type.dart' as engine;
+import 'package:analyzer/src/dart/ast/utilities.dart' as engine;
 import 'package:analyzer/src/dart/element/element.dart' as engine;
-import 'package:analyzer/src/generated/ast.dart' as engine;
 import 'package:analyzer/src/generated/error.dart' as engine;
 import 'package:analyzer/src/generated/source.dart' as engine;
 import 'package:test_reflective_loader/test_reflective_loader.dart';