move import combinator suggestions into a separate computer

pkg/analysis_server/test/services/completion/test_all.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;
 
 import 'package:unittest/unittest.dart';
 
+import 'combinator_computer_test.dart' as combinator_test;
 import 'completion_computer_test.dart' as completion_computer_test;
 import 'completion_manager_test.dart' as completion_manager_test;
 import 'imported_computer_test.dart' as imported_test;
 import 'invocation_computer_test.dart' as invocation_test;
 import 'keyword_computer_test.dart' as keyword_test;
 import 'local_computer_test.dart' as local_test;
 
 /// Utility for manually running all tests.
 main() {
   groupSep = ' | ';
   group('completion', () {
+    combinator_test.main();
     completion_computer_test.main();
     completion_manager_test.main();
     imported_test.main();
     keyword_test.main();
     invocation_test.main();
     local_test.main();
   });
 }