Stop using RESOLVED_UNIT_x for other libraries.

pkg/analyzer/test/src/context/context_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 analyzer.test.src.context.context_test;
 
 import 'dart:async';
 
 import 'package:analyzer/dart/element/element.dart';
 import 'package:analyzer/dart/element/type.dart';
@@ skipping 1926 matching lines @@
     context.onResultComputed(RESOLVED_UNIT).listen((event) {
       LibrarySpecificUnit target = event.target;
       Source librarySource = target.library;
       resolvedUnitUris.add(librarySource.uri.toString());
     });
     // analyze
     addSource('/test.dart', 'main() {}');
     _analyzeAll_assertFinished();
     // verify
     expect(libraryElementUris, contains('file:///test.dart'));
-    expect(parsedUnitUris, contains('dart:core'));
     expect(parsedUnitUris, contains('file:///test.dart'));
-    expect(resolvedUnitUris, contains('dart:core'));
     expect(resolvedUnitUris, contains('file:///test.dart'));
   }
 
   void test_performAnalysisTask_switchPackageVersion() {
     // version 1
     resourceProvider.newFile(
         '/pkgs/crypto-1/lib/crypto.dart',
         r'''
 library crypto;
 part 'src/hash_utils.dart';
@@ skipping 766 matching lines @@
   int get modificationStamp => stamp;
 }
 
 class _AnalysisContextImplTest_test_applyChanges_removeContainer
     implements SourceContainer {
   Source libB;
   _AnalysisContextImplTest_test_applyChanges_removeContainer(this.libB);
   @override
   bool contains(Source source) => source == libB;
 }