Fix warnings_checker.dart handling of multitests

tests/language/rewrite_implicit_this_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.
 
 import "package:expect/expect.dart";
 
 String toplevel = 'A';
 
 class Foo {
     String x = 'x';
 
     easy(z) {
-        return x + y + z; /// 01: static type warning
+        return x + y + z; //# 01: static type warning
     }
 
     // Shadow the 'y' field in various ways
     shadow_y_parameter(y) {
-        return x + this.y + y; /// 01: continued
+        return x + this.y + y; //# 01: continued
     }
 
     shadow_y_local(z) {
         var y = z;
-        return x + this.y + y; /// 01: continued
+        return x + this.y + y; //# 01: continued
     }
 
     shadow_y_capturedLocal(z) {
         var y = z;
         foo() {
-            return x + this.y + y; /// 01: continued
+            return x + this.y + y; //# 01: continued
         }
         return foo();
     }
 
     shadow_y_closureParam(z) {
         foo(y) {
-            return x + this.y + y; /// 01: continued
+            return x + this.y + y; //# 01: continued
         }
         return foo(z);
     }
 
     shadow_y_localInsideClosure(z) {
         foo() {
             var y = z;
-            return x + this.y + y; /// 01: continued
+            return x + this.y + y; //# 01: continued
         }
         return foo();
     }
 
     // Shadow the 'x' field in various ways
     shadow_x_parameter(x) {
-        return this.x + y + x; /// 01: continued
+        return this.x + y + x; //# 01: continued
     }
 
     shadow_x_local(z) {
         var x = z;
-        return this.x + y + x; /// 01: continued
+        return this.x + y + x; //# 01: continued
     }
 
     shadow_x_capturedLocal(z) {
         var x = z;
         foo() {
-            return this.x + y + x; /// 01: continued
+            return this.x + y + x; //# 01: continued
         }
         return foo();
     }
 
     shadow_x_closureParam(z) {
         foo(x) {
-            return this.x + y + x; /// 01: continued
+            return this.x + y + x; //# 01: continued
         }
         return foo(z);
     }
 
     shadow_x_localInsideClosure(z) {
         foo() {
             var x = z;
-            return this.x + y + x; /// 01: continued
+            return this.x + y + x; //# 01: continued
         }
         return foo();
     }
 
     shadow_x_toplevel() {
-        return x + this.y + toplevel + this.toplevel; /// 01: continued
+        return x + this.y + toplevel + this.toplevel; //# 01: continued
     }
     
 }
 
 class Sub extends Foo {
     String y = 'y';
     String toplevel = 'B';
 }
 
 main() {
-    Expect.equals('xyz', new Sub().easy('z')); /// 01: continued
-    Expect.equals('xyz', new Sub().shadow_y_parameter('z')); /// 01: continued
-    Expect.equals('xyz', new Sub().shadow_y_local('z')); /// 01: continued
-    Expect.equals('xyz', new Sub().shadow_y_capturedLocal('z')); /// 01: continued
-    Expect.equals('xyz', new Sub().shadow_y_closureParam('z')); /// 01: continued
-    Expect.equals('xyz', new Sub().shadow_y_localInsideClosure('z')); /// 01: continued
-    Expect.equals('xyz', new Sub().shadow_x_parameter('z')); /// 01: continued
-    Expect.equals('xyz', new Sub().shadow_x_local('z')); /// 01: continued
-    Expect.equals('xyz', new Sub().shadow_x_capturedLocal('z')); /// 01: continued
-    Expect.equals('xyz', new Sub().shadow_x_closureParam('z')); /// 01: continued
-    Expect.equals('xyz', new Sub().shadow_x_localInsideClosure('z')); /// 01: continued
+    Expect.equals('xyz', new Sub().easy('z')); //# 01: continued
+    Expect.equals('xyz', new Sub().shadow_y_parameter('z')); //# 01: continued
+    Expect.equals('xyz', new Sub().shadow_y_local('z')); //# 01: continued
+    Expect.equals('xyz', new Sub().shadow_y_capturedLocal('z')); //# 01: continued
+    Expect.equals('xyz', new Sub().shadow_y_closureParam('z')); //# 01: continued
+    Expect.equals('xyz', new Sub().shadow_y_localInsideClosure('z')); //# 01: continued
+    Expect.equals('xyz', new Sub().shadow_x_parameter('z')); //# 01: continued
+    Expect.equals('xyz', new Sub().shadow_x_local('z')); //# 01: continued
+    Expect.equals('xyz', new Sub().shadow_x_capturedLocal('z')); //# 01: continued
+    Expect.equals('xyz', new Sub().shadow_x_closureParam('z')); //# 01: continued
+    Expect.equals('xyz', new Sub().shadow_x_localInsideClosure('z')); //# 01: continued
 
-    Expect.equals('xyAB', new Sub().shadow_x_toplevel()); /// 01: continued
+    Expect.equals('xyAB', new Sub().shadow_x_toplevel()); //# 01: continued
 }