Use an import prefix in the analysis server tests; this fixes some issues conflicting with the

pkg/analysis_server/test/integration/analysis/package_root_test.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 test.integration.analysis.packageRoot;
 
 import 'package:analysis_server/plugin/protocol/protocol.dart';
-import 'package:path/path.dart';
+import 'package:path/path.dart' as path;
 import 'package:test/test.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
 
 import '../integration_tests.dart';
 
 main() {
   defineReflectiveSuite(() {
     defineReflectiveTests(Test);
   });
 }
 
 @reflectiveTest
 class Test extends AbstractAnalysisServerIntegrationTest {
   test_package_root() {
     String projPath = sourcePath('project');
-    String mainPath = join(projPath, 'main.dart');
+    String mainPath = path.join(projPath, 'main.dart');
     String packagesPath = sourcePath('packages');
-    String fooBarPath = join(packagesPath, 'foo', 'bar.dart');
+    String fooBarPath = path.join(packagesPath, 'foo', 'bar.dart');
     String mainText = """
 library main;
 
 import 'package:foo/bar.dart'
 
 main() {
   f();
 }
 """;
     String fooBarText = """
@@ skipping 33 matching lines @@
               navigationTargets[navigationTargetIndex];
           String navigationFile =
               navigationTargetFiles[navigationTarget.fileIndex];
           expect(navigationFile, equals(normalizedFooBarPath));
         }
       }
       expect(found, isTrue);
     });
   }
 }