extract LabelContributor from local reference contributor

pkg/analysis_server/test/services/completion/completion_test_util.dart

Index: pkg/analysis_server/test/services/completion/completion_test_util.dart
diff --git a/pkg/analysis_server/test/services/completion/completion_test_util.dart b/pkg/analysis_server/test/services/completion/completion_test_util.dart
index 7812fd8e8c4d92f55be1e14aae31e44e29ad61cf..663acf3bf765f5a2c55baab78a64c6b67db4ea0f 100644
--- a/pkg/analysis_server/test/services/completion/completion_test_util.dart
+++ b/pkg/analysis_server/test/services/completion/completion_test_util.dart
@@ -305,23 +305,6 @@ abstract class AbstractCompletionTest extends AbstractContextTest {
     return cs;
   }
 
-  CompletionSuggestion assertSuggestLabel(String name,
-      [int relevance = DART_RELEVANCE_DEFAULT,
-      CompletionSuggestionKind kind = CompletionSuggestionKind.IDENTIFIER]) {
-    CompletionSuggestion cs =
-        assertSuggest(name, csKind: kind, relevance: relevance);
-    expect(cs.returnType, isNull);
-    protocol.Element element = cs.element;
-    expect(element, isNotNull);
-    expect(element.flags, 0);
-    expect(element.kind, equals(protocol.ElementKind.LABEL));
-    expect(element.name, equals(name));
-    expect(element.parameters, isNull);
-    expect(element.returnType, isNull);
-    assertHasNoParameterInfo(cs);
-    return cs;
-  }
-
   CompletionSuggestion assertSuggestLibraryPrefix(String prefix,
       [int relevance = DART_RELEVANCE_DEFAULT,
       CompletionSuggestionKind kind = CompletionSuggestionKind.INVOCATION]) {