extract StaticMemberContributor from PrefixedElementContributor

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/plugin/protocol/protocol.dart' as protocol
     show Element, ElementKind;
@@ skipping 3842 matching lines @@
     addTestSource('''
       import "/testB.dart";
       class A extends B {
         static const String scA = 'foo';
         w() { }}
       main() {A.^}''');
     computeFast();
     return computeFull((bool result) {
       expect(request.replacementOffset, completionOffset);
       expect(request.replacementLength, 0);
-      assertSuggestInvocationField('scA', 'String');
-      assertSuggestInvocationField('scB', 'int');
-      assertSuggestInvocationField('scI', null);
+      // Suggested by StaticMemberContributor
+      assertNotSuggested('scA');
+      assertNotSuggested('scB');
+      assertNotSuggested('scI');
       assertNotSuggested('b');
       assertNotSuggested('_c');
       assertNotSuggested('d');
       assertNotSuggested('_e');
       assertNotSuggested('f');
       assertNotSuggested('_g');
       assertNotSuggested('s1');
       assertNotSuggested('_s2');
       assertNotSuggested('m');
       assertNotSuggested('_n');
@@ skipping 819 matching lines @@
       assertNotSuggested('bar2');
       assertNotSuggested('_B');
       assertSuggestLocalClass('Y');
       assertSuggestLocalClass('C');
       assertSuggestLocalVariable('f', null);
       assertNotSuggested('x');
       assertNotSuggested('e');
     });
   }
 }