Revert "Store actual Reference(s) for additional exports."

pkg/front_end/test/src/incremental/kernel_driver_test.dart

 // Copyright (c) 2017, 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 'dart:async';
 
 import 'package:front_end/compiler_options.dart';
 import 'package:front_end/memory_file_system.dart';
 import 'package:front_end/src/base/performace_logger.dart';
 import 'package:front_end/src/base/processed_options.dart';
@@ skipping 90 matching lines @@
 static method main() → void {}
 ''');
     }
   }
 
   test_compile_export() async {
     writeFile('/test/.packages', 'test:lib/');
     String aPath = '/test/lib/a.dart';
     String bPath = '/test/lib/b.dart';
     String cPath = '/test/lib/c.dart';
-    String dPath = '/test/lib/d.dart';
     writeFile(aPath, 'class A {}');
-    Uri bUri = writeFile(bPath, 'export "a.dart";');
-    Uri cUri = writeFile(cPath, 'export "b.dart";');
-    Uri dUri = writeFile(dPath, r'''
-import 'c.dart';
+    writeFile(bPath, 'export "a.dart";');
+    Uri cUri = writeFile(cPath, r'''
+import 'b.dart';
 A a;
 ''');
 
-    KernelResult result = await driver.getKernel(dUri);
-    Library library = _getLibrary(result, dUri);
-    expect(_getLibraryText(_getLibrary(result, bUri)), r'''
-library;
-import self as self;
-import "./a.dart" as a;
-additionalExports = (a::A)
-
-''');
-    expect(_getLibraryText(_getLibrary(result, cUri)), r'''
-library;
-import self as self;
-import "./a.dart" as a;
-additionalExports = (a::A)
-
-''');
+    KernelResult result = await driver.getKernel(cUri);
+    Library library = _getLibrary(result, cUri);
     expect(_getLibraryText(library), r'''
 library;
 import self as self;
 import "./a.dart" as a;
 
 static field a::A a;
 ''');
   }
 
   test_compile_export_cycle() async {
@@ skipping 638 matching lines @@
         .writeLibraryFile(library);
     return buffer.toString();
   }
 
   /// Return the [Uri] for the given Posix [path].
   static Uri _folderUri(String path) {
     if (!path.endsWith('/')) path += '/';
     return Uri.parse('file://$path');
   }
 }