Fix warnings_checker.dart handling of multitests

tests/language_strong/async_await_test.dart

 // Copyright (c) 2015, 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 async_await_test;
 
 import "package:unittest/unittest.dart";
 import "dart:async";
 
 main() {
@@ skipping 1713 matching lines @@
     test("top-level getter call", () {
       f() async {
         var a = new Async();
         return await a.instanceGetter;
       }
       return expect42(f());
     });
 
     if (!checkedMode) return;
 
-    test("inside assert, true", () { //                      /// 03: ok
-      f() async { //                                         /// 03: continued
-        assert(await new Future.microtask(() => true)); //   /// 03: continued
-        return 42; //                                        /// 03: continued
-      } //                                                   /// 03: continued
-      return expect42(f()); //                               /// 03: continued
-    }); //                                                   /// 03: continued
+    test("inside assert, true", () { //                      //# 03: ok
+      f() async { //                                         //# 03: continued
+        assert(await new Future.microtask(() => true)); //   //# 03: continued
+        return 42; //                                        //# 03: continued
+      } //                                                   //# 03: continued
+      return expect42(f()); //                               //# 03: continued
+    }); //                                                   //# 03: continued
 
-    test("inside assert, false", () { //                     /// 03: continued
-      f() async { //                                         /// 03: continued
-        assert(await new Future.microtask(() => false)); //  /// 03: continued
-        return 42; //                                        /// 03: continued
-      } //                                                   /// 03: continued
-      return f().then((_) { //                               /// 03: continued
-        fail("assert didn't throw"); //                      /// 03: continued
-      }, onError: (e, s) { //                                /// 03: continued
-        expect(e is AssertionError, isTrue); //              /// 03: continued
-      }); //                                                 /// 03: continued
-    }); //                                                   /// 03: continued
+    test("inside assert, false", () { //                     //# 03: continued
+      f() async { //                                         //# 03: continued
+        assert(await new Future.microtask(() => false)); //  //# 03: continued
+        return 42; //                                        //# 03: continued
+      } //                                                   //# 03: continued
+      return f().then((_) { //                               //# 03: continued
+        fail("assert didn't throw"); //                      //# 03: continued
+      }, onError: (e, s) { //                                //# 03: continued
+        expect(e is AssertionError, isTrue); //              //# 03: continued
+      }); //                                                 //# 03: continued
+    }); //                                                   //# 03: continued
 
-    test("inside assert, function -> false", () { //         /// 03: continued
-      f() async { //                                         /// 03: continued
-        assert(await new Future.microtask(() => false)); //  /// 03: continued
-        return 42; //                                        /// 03: continued
-      } //                                                   /// 03: continued
-      return f().then((_) { //                               /// 03: continued
-        fail("assert didn't throw"); //                      /// 03: continued
-      }, onError: (e, s) { //                                /// 03: continued
-        expect(e is AssertionError, isTrue); //              /// 03: continued
-      }); //                                                 /// 03: continued
-    }); //                                                   /// 03: continued
+    test("inside assert, function -> false", () { //         //# 03: continued
+      f() async { //                                         //# 03: continued
+        assert(await new Future.microtask(() => false)); //  //# 03: continued
+        return 42; //                                        //# 03: continued
+      } //                                                   //# 03: continued
+      return f().then((_) { //                               //# 03: continued
+        fail("assert didn't throw"); //                      //# 03: continued
+      }, onError: (e, s) { //                                //# 03: continued
+        expect(e is AssertionError, isTrue); //              //# 03: continued
+      }); //                                                 //# 03: continued
+    }); //                                                   //# 03: continued
 
   });
 
   group("syntax", () {
     test("async as variable", () {
       // Valid identifiers outside of async function.
       var async = 42;
       expect(async, equals(42));
     });
 
-    test("await as variable", () { //                        /// 02: ok
-      // Valid identifiers outside of async function. //     /// 02: continued
-      var await = 42; //                                     /// 02: continued
-      expect(await, equals(42)); //                          /// 02: continued
-    }); //                                                   /// 02: continued
+    test("await as variable", () { //                        //# 02: ok
+      // Valid identifiers outside of async function. //     //# 02: continued
+      var await = 42; //                                     //# 02: continued
+      expect(await, equals(42)); //                          //# 02: continued
+    }); //                                                   //# 02: continued
 
     test("yield as variable", () {
       // Valid identifiers outside of async function.
       var yield = 42;
       expect(yield, equals(42));
     });
   });
 }
 
 
@@ skipping 212 matching lines @@
       if (onError is BinaryFunction) {
         return onError(_error, null);
       }
       return onError(_error);
     });
   }
   Stream asStream() =>
       (new StreamController()..addError(_error)..close()).stream;
   Future timeout(Duration duration, {onTimeout()}) => this;
 }