move combinator contributor to new task model

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

Index: pkg/analysis_server/test/services/completion/dart/test_all.dart
diff --git a/pkg/analysis_server/test/services/completion/dart/test_all.dart b/pkg/analysis_server/test/services/completion/dart/test_all.dart
index dffcb38eb27b5359b288c4d3ad2c0c91f769e915..9d8d0617e4611fe2d52813b1742e2241f653227e 100644
--- a/pkg/analysis_server/test/services/completion/dart/test_all.dart
+++ b/pkg/analysis_server/test/services/completion/dart/test_all.dart
@@ -7,6 +7,7 @@ library test.services.completion.dart;
 import 'package:unittest/unittest.dart';
 
 import '../../../utils.dart';
+import 'combinator_contributor_test.dart' as combinator_test;
 import 'arglist_contributor_test.dart' as arglist_test;
 import 'common_usage_sorter_test.dart' as common_usage_test;
 import 'inherited_contributor_test.dart' as inherited_contributor_test;
@@ -18,6 +19,7 @@ main() {
   initializeTestEnvironment();
   group('dart/completion', () {
     arglist_test.main();
+    combinator_test.main();
     common_usage_test.main();
     inherited_contributor_test.main();
     keyword_test.main();