Fix warnings_checker.dart handling of multitests

tests/standalone/packages_file_test.dart

 // Copyright (c) 2016, 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.
 
 import "dart:async";
 import "dart:io";
 import "dart:convert" show JSON;
 import "package:path/path.dart" as p;
 import "package:async_helper/async_helper.dart";
 
@@ skipping 10 matching lines @@
 List<Configuration> configurations = [];
 /// Collection of failing tests and their failure messages.
 ///
 /// Each test may fail in more than one way.
 var failingTests = <String, List<String>>{};
 
 main() async {
   asyncStart();
   await setUp();
 
-  await runTests(); //                         /// 01: ok
-  await runTests([spawn]); //                  /// 02: ok
-  await runTests([spawn, spawn]); //           /// 03: ok
-  await runTests([spawnUriInherit]); //        /// 04: ok
-  await runTests([spawnUriInherit, spawn]); // /// 05: ok
-  await runTests([spawn, spawnUriInherit]); // /// 06: ok
+  await runTests(); //                         //# 01: ok
+  await runTests([spawn]); //                  //# 02: ok
+  await runTests([spawn, spawn]); //           //# 03: ok
+  await runTests([spawnUriInherit]); //        //# 04: ok
+  await runTests([spawnUriInherit, spawn]); // //# 05: ok
+  await runTests([spawn, spawnUriInherit]); // //# 06: ok
 
   // Test that spawning a new VM with file paths instead of URIs as arguments
   // gives the same URIs in the internal values.
-  await runTests([asPath]); //                 /// 07: ok
+  await runTests([asPath]); //                 //# 07: ok
 
   // Test that spawnUri can reproduce the behavior of VM command line parameters
   // exactly.
   // (Don't run all configuration combinations in the same test, so
   // unroll the configurations into multiple groups and run each group
   // as its own multitest.
   {
     var groupCount = 8;
     var groups = new List.generate(8, (_)=>[]);
     for (int i = 0; i < configurations.length; i++) {
       groups[i % groupCount].add(configurations[i]);
     }
     var group = -1;
-    group = 0; //                              /// 10: ok
-    group = 1; //                              /// 11: ok
-    group = 2; //                              /// 12: ok
-    group = 3; //                              /// 13: ok
-    group = 4; //                              /// 14: ok
-    group = 5; //                              /// 15: ok
-    group = 6; //                              /// 16: ok
-    group = 7; //                              /// 17: ok
+    group = 0; //                              //# 10: ok
+    group = 1; //                              //# 11: ok
+    group = 2; //                              //# 12: ok
+    group = 3; //                              //# 13: ok
+    group = 4; //                              //# 14: ok
+    group = 5; //                              //# 15: ok
+    group = 6; //                              //# 16: ok
+    group = 7; //                              //# 17: ok
     if (group >= 0) {
       for (var other in groups[group]) {
         await runTests([spawnUriOther(other)]);
       }
     }
   }
 
 
   await tearDown();
 
@@ skipping 905 matching lines @@
 void insertFileAt(Map file, Map http,
                   String path, String name, String content) {
   var parts = path.split('/').toList();
   var dir = (parts[0] == "%file") ? file : http;
   for (var i = 1; i < parts.length - 1; i++) {
     var entry = parts[i];
     dir = dir[entry] ?? (dir[entry] = {});
   }
   dir[name] = content;
 }