Restore partial analysis of analysis options files

pkg/analysis_server/test/domain_diagnostic_test.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:analysis_server/protocol/protocol_generated.dart';
 import 'package:analysis_server/src/domain_diagnostic.dart';
 import 'package:test/test.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
 
 import 'analysis_abstract.dart';
@@ skipping 26 matching lines @@
     var request = new DiagnosticGetDiagnosticsParams().toRequest('0');
     var response = handler.handleRequest(request);
     var result = new DiagnosticGetDiagnosticsResult.fromResponse(response);
 
     expect(result.contexts, hasLength(1));
 
     ContextData context = result.contexts[0];
     expect(context.name, '/project');
     expect(context.explicitFileCount, 1); /* test.dart */
 
-    expect(context.implicitFileCount, 4);
+    expect(context.implicitFileCount, 5);
 
     expect(context.workItemQueueLength, isNotNull);
   }
 
   test_getDiagnostics_noRoot() async {
     var request = new DiagnosticGetDiagnosticsParams().toRequest('0');
     var response = handler.handleRequest(request);
     var result = new DiagnosticGetDiagnosticsResult.fromResponse(response);
     expect(result.contexts, isEmpty);
   }
 }