Resolve obvious deprecation warnings on bleeding edge

lib/src/codegen/js_interop.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.
 
-import 'package:analyzer/src/generated/ast.dart';
+import 'package:analyzer/dart/ast/ast.dart';
 import 'package:analyzer/src/generated/constant.dart';
-import 'package:analyzer/src/generated/element.dart';
+import 'package:analyzer/dart/element/element.dart';
 import 'package:analyzer/src/generated/resolver.dart' show TypeProvider;
 
 import '../utils.dart';
 
 bool _isJsLibType(String expectedName, Element e) =>
     e?.name == expectedName && _isJsLib(e.library);
 
 /// Returns true if [e] represents any library from `package:js` or is the
 /// internal `dart:_js_helper` library.
 bool _isJsLib(LibraryElement e) {
@@ skipping 46 matching lines @@
 /// Returns the name value of the `JSExportName` annotation (when compiling
 /// the SDK), or `null` if there's none. This is used to control the name
 /// under which functions are compiled and exported.
 String getJSExportName(Element e, TypeProvider types) {
   if (!e.source.isInSystemLibrary) {
     return null;
   }
   var jsName = findAnnotation(e, isJSExportNameAnnotation);
   return getConstantField(jsName, 'name', types.stringType)?.toStringValue();
 }