Remove unintentional dependency on analysis_server

pkg/analysis_server/test/integration/coverage_test.dart

 // Copyright (c) 2017, 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 'dart:io';
 
-import 'package:analysis_server/src/services/correction/strings.dart';
+import 'package:analyzer_plugin/src/utilities/string_utilities.dart';
 import 'package:path/path.dart' as path;
 import 'package:test/test.dart';
 
 import '../../tool/spec/api.dart';
 import '../../tool/spec/from_html.dart';
 
 /// Define tests to fail if there's no mention in the coverage file.
 main() {
   Api api;
   File coverageFile;
@@ skipping 74 matching lines @@
 
   // validate no unexpected domains
   group('integration coverage', () {
     test('no unexpected domains', () {
       for (String domain in coveredDomains) {
         expect(api.domains.map((d) => d.name), contains(domain));
       }
     });
   });
 }