Arglist `children:` default value gen fixes.

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

Index: pkg/analysis_server/test/services/completion/dart/completion_contributor_util.dart
diff --git a/pkg/analysis_server/test/services/completion/dart/completion_contributor_util.dart b/pkg/analysis_server/test/services/completion/dart/completion_contributor_util.dart
index eec6ebf56f285f1700b91a1359adc3574ae085c9..1ded0a58a135277d6ce4bf6aeefcf2cb32b2be98 100644
--- a/pkg/analysis_server/test/services/completion/dart/completion_contributor_util.dart
+++ b/pkg/analysis_server/test/services/completion/dart/completion_contributor_util.dart
@@ -210,12 +210,14 @@ abstract class DartCompletionContributorTest extends AbstractContextTest {
       {int relevance: DART_RELEVANCE_DEFAULT,
       String importUri,
       int elemOffset,
-      String defaultArgListString}) {
+      String defaultArgListString,
+      List<int> defaultArgumentListTextRanges}) {
     CompletionSuggestion cs = assertSuggest(name,
         relevance: relevance,
         importUri: importUri,
         elemOffset: elemOffset,
-        defaultArgListString: defaultArgListString);
+        defaultArgListString: defaultArgListString,
+        defaultArgumentListTextRanges: defaultArgumentListTextRanges);
     protocol.Element element = cs.element;
     expect(element, isNotNull);
     expect(element.kind, equals(protocol.ElementKind.CONSTRUCTOR));