fix NSM error when completing imported inherited private fields

pkg/analysis_server/test/services/completion/completion_test_util.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.services.completion.util;
 
 import 'dart:async';
 
 import 'package:analysis_server/src/protocol.dart' as protocol
     show Element, ElementKind;
@@ skipping 1367 matching lines @@
       assertNotSuggested('==');
       // TODO (danrubel) suggest HtmlElement as low relevance
       assertNotSuggested('HtmlElement');
     });
   }
 
   test_Block_inherited_imported() {
     // Block  BlockFunctionBody  MethodDeclaration  ClassDeclaration
     addSource('/testB.dart', '''
       lib B;
-      class F { var f1; f2() { } get f3 => 0; set f4(fx) { } }
+      class F { var f1; f2() { } get f3 => 0; set f4(fx) { } var _pf; }
       class E extends F { var e1; e2() { } }
       class I { int i1; i2() { } }
       class M { var m1; int m2() { } }''');
     addTestSource('''
       import "/testB.dart";
       class A extends E implements I with M {a() {^}}''');
     computeFast();
     return computeFull((bool result) {
       expect(request.replacementOffset, completionOffset);
       expect(request.replacementLength, 0);
@@ skipping 2310 matching lines @@
       assertNotSuggested('bar2');
       assertNotSuggested('_B');
       assertSuggestLocalClass('Y');
       assertSuggestLocalClass('C');
       assertSuggestLocalVariable('f', null);
       assertNotSuggested('x');
       assertNotSuggested('e');
     });
   }
 }