Clean up imports in analysis_server and analyzer_cli (and one missed in analyzer)

pkg/analysis_server/lib/src/services/correction/namespace.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 services.src.correction.namespace;
 
+import 'package:analyzer/dart/element/element.dart';
 import 'package:analyzer/src/generated/ast.dart';
-import 'package:analyzer/src/generated/element.dart';
 import 'package:analyzer/src/generated/resolver.dart';
 
 /**
  * Returns the [Element] exported from the given [LibraryElement].
  */
 Element getExportedElement(LibraryElement library, String name) {
   if (library == null) {
     return null;
   }
   return getExportNamespaceForLibrary(library)[name];
@@ skipping 154 matching lines @@
 }
 
 /**
  * Information about [ImportElement] and place where it is referenced using
  * [PrefixElement].
  */
 class ImportElementInfo {
   ImportElement element;
   int periodEnd;
 }