remove complex keyword suggestions - fixes #23978

pkg/analysis_server/test/completion_test.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.completion.support;
 
 import 'dart:async';
 import 'dart:collection';
 
 import 'package:unittest/unittest.dart';
@@ skipping 2601 matching lines @@
     } !Bon Object !Ccatch(a){}
     !Fassert true;
     !Jif (x) {} !Kelse {};
     !Lreturn;
   }
 }''',
         <String>[
           "1+while",
           "2+do",
           "3+while",
-          "4+for (!)",
+          "4+for",
           "5+in",
-          "6+for (!)",
+          "6+for",
           "7+switch",
           "8+case",
           "9+default",
           "A+try",
           "B+on",
           "C+catch",
           "D+var",
           "E+void",
           "F+assert",
           "G+continue",
@@ skipping 17 matching lines @@
 
     // keywords
     buildTests(
         'test017',
         '''
 !1!2import 'x' !5as r;
 !3export '!8uri' !6hide Q !7show X;
 !4part 'x';''',
         <String>[
           "1+library",
-          "2+import '!';",
+          "2+import",
           "3+export",
           "4+part",
           "5+as",
           "6+hide",
           "7+show",
           "8-null"
         ],
         failingTests: '567');
 
     // keywords
@@ skipping 321 matching lines @@
       } else {
         ++expectedPassCount;
         tester(testName, () {
           CompletionTestCase test = new CompletionTestCase();
           return test.runTest(spec, extraFiles);
         });
       }
     }
   }
 }