Deprecate the generated AST library and clean up imports

pkg/analysis_server/lib/src/protocol_server.dart

Index: pkg/analysis_server/lib/src/protocol_server.dart
diff --git a/pkg/analysis_server/lib/src/protocol_server.dart b/pkg/analysis_server/lib/src/protocol_server.dart
index 00f749e5a00d61d9bc6b7478ea955207c1eebdb2..138c20f1ca65f25962d436027c0acd3079ef6b70 100644
--- a/pkg/analysis_server/lib/src/protocol_server.dart
+++ b/pkg/analysis_server/lib/src/protocol_server.dart
@@ -9,10 +9,12 @@ import 'package:analysis_server/plugin/protocol/protocol_dart.dart';
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analysis_server/src/services/search/search_engine.dart'
     as engine;
+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/source/error_processor.dart';
-import 'package:analyzer/src/generated/ast.dart' as engine;
+import 'package:analyzer/src/dart/ast/utilities.dart' as engine;
 import 'package:analyzer/src/generated/engine.dart' as engine;
 import 'package:analyzer/src/generated/error.dart' as engine;
 import 'package:analyzer/src/generated/source.dart' as engine;