Clean-up imports

pkg/analyzer/test/src/task/incremental_element_builder_test.dart

 // Copyright (c) 2015, 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 analyzer.test.src.task.incremental_element_builder_test;
 
+import 'package:analyzer/dart/ast/ast.dart';
 import 'package:analyzer/dart/element/element.dart';
-import 'package:analyzer/src/generated/ast.dart';
 import 'package:analyzer/src/generated/source.dart';
 import 'package:analyzer/src/task/incremental_element_builder.dart';
 import 'package:unittest/unittest.dart';
 
 import '../../reflective_tests.dart';
 import '../../utils.dart';
 import '../context/abstract_context.dart';
 
 main() {
   initializeTestEnvironment();
@@ skipping 666 matching lines @@
     this.oldCode = oldCode;
     source = newSource('/test.dart', oldCode);
     if (libSource == null) {
       libSource = source;
     }
     oldUnit = context.resolveCompilationUnit2(source, libSource);
     unitElement = oldUnit.element;
     expect(unitElement, isNotNull);
   }
 }