Switch analysis_server to use 'package:test'.

pkg/analysis_server/test/integration/analysis/get_errors.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.get.errors;
 
 import 'dart:async';
 
-import 'package:unittest/unittest.dart';
+import 'package:test/test.dart';
 
 import '../integration_tests.dart';
 
 /**
  * Base class for testing the "analysis.getErrors" request.
  */
 class AnalysisDomainGetErrorsTest
     extends AbstractAnalysisServerIntegrationTest {
   /**
    * True if the "analysis.getErrors" request should be made after analysis is
@@ skipping 16 matching lines @@
         expect(result.errors, equals(currentAnalysisErrors[pathname]));
       });
     }
     if (afterAnalysis) {
       return analysisFinished.then((_) => finishTest());
     } else {
       return finishTest();
     }
   }
 }