Use async/await in all analysis domain tests.

pkg/analysis_server/test/analysis/notification_analyzedFiles_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.analysis.notification.analyzedDirectories;
 
 import 'dart:async';
 
 import 'package:analysis_server/plugin/protocol/protocol.dart';
 import 'package:analysis_server/src/constants.dart';
@@ skipping 31 matching lines @@
       analyzedFilesReceived = true;
       analyzedFiles = params.directories;
     }
   }
 
   void setUp() {
     super.setUp();
     createProject();
   }
 
-  test_afterAnalysis() {
+  test_afterAnalysis() async {
     addTestFile('''
 class A {}
 ''');
-    return waitForTasksFinished().then((_) {
-      return prepareAnalyzedFiles().then((_) {
-        assertHasFile(testFile);
-      });
-    });
+    await waitForTasksFinished();
+    await prepareAnalyzedFiles();
+    assertHasFile(testFile);
   }
 
-  test_beforeAnalysis() {
+  test_beforeAnalysis() async {
     addTestFile('''
 class A {}
 ''');
-    return prepareAnalyzedFiles().then((_) {
-      assertHasFile(testFile);
-    });
+    await prepareAnalyzedFiles();
+    assertHasFile(testFile);
   }
 
   test_insignificant_change() async {
     // Making a change that doesn't affect the set of reachable files should
     // not trigger the notification to be re-sent.
     addTestFile('class A {}');
     await prepareAnalyzedFiles();
     await waitForTasksFinished();
     expect(analyzedFilesReceived, isTrue);
     analyzedFilesReceived = false;
@@ skipping 30 matching lines @@
     await pumpEventQueue();
     await waitForTasksFinished();
     expect(analyzedFilesReceived, isTrue);
     assertHasFile('/foo.dart');
   }
 
   void unsubscribeAnalyzedFiles() {
     removeGeneralAnalysisSubscription(GeneralAnalysisService.ANALYZED_FILES);
   }
 }