Port two completion contributors for use by plugins

pkg/analyzer_plugin/test/utilities/test_all.dart

Index: pkg/analyzer_plugin/test/utilities/test_all.dart
diff --git a/pkg/analyzer_plugin/test/utilities/test_all.dart b/pkg/analyzer_plugin/test/utilities/test_all.dart
index 46d9cd2e9120cf2b29f4dda0c74c1cc6e856a51d..7cc0dd2b260d1c4bc5a2a38839ae7b003c8ff4f1 100644
--- a/pkg/analyzer_plugin/test/utilities/test_all.dart
+++ b/pkg/analyzer_plugin/test/utilities/test_all.dart
@@ -5,6 +5,7 @@
 import 'package:test_reflective_loader/test_reflective_loader.dart';
 
 import 'analyzer_converter_test.dart' as analyzer_converter_test;
+import 'completion/test_all.dart' as completion;
 import 'navigation_test.dart' as navigation_test;
 import 'range_factory_test.dart' as range_factory_test;
 import 'subscriptions/test_all.dart' as subscriptions;
@@ -12,6 +13,7 @@ import 'subscriptions/test_all.dart' as subscriptions;
 main() {
   defineReflectiveSuite(() {
     analyzer_converter_test.main();
+    completion.main();
     navigation_test.main();
     range_factory_test.main();
     subscriptions.main();