Create `loadLibrary` function element eagerly.

pkg/analyzer/test/src/task/dart_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.
 
 library test.src.task.dart_test;
 
 import 'package:analyzer/src/context/cache.dart';
 import 'package:analyzer/src/generated/ast.dart';
 import 'package:analyzer/src/generated/constant.dart';
 import 'package:analyzer/src/generated/element.dart';
@@ skipping 3190 matching lines @@
     // validate
     LibraryElement library = outputs[LIBRARY_ELEMENT5];
     {
       ClassElement classB = library.getType('B');
       expect(classB.supertype.displayName, 'A');
     }
     {
       ClassElement classC = library.getType('C');
       expect(classC.supertype.displayName, 'A');
     }
+    expect(library.loadLibraryFunction, isNotNull);
   }
 
   test_perform_external() {
     Source sourceA = newSource(
         '/a.dart',
         '''
 library a;
 import 'b.dart';
 class A extends B {}
 ''');
@@ skipping 1087 matching lines @@
   /**
    * Fill [errorListener] with [result] errors in the current [task].
    */
   void _fillErrorListener(ResultDescriptor<List<AnalysisError>> result) {
     List<AnalysisError> errors = task.outputs[result];
     expect(errors, isNotNull, reason: result.name);
     errorListener = new GatheringErrorListener();
     errorListener.addAll(errors);
   }
 }