Fix warnings_checker.dart handling of multitests

tests/language/compile_time_constant_checked3_test.dart

 // Copyright (c) 2012, 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.
 
 class A {
   final int x;
-  const A.a1() : x = 'foo'; /// 01: continued
+  const A.a1() : x = 'foo'; //# 01: continued
   const A.a2(this.x);
-  const A.a3([this.x = 'foo']); /// 03: continued
-  const A.a4(String this.x); /// 04: continued
-  const A.a5(String x) : this.x = x; /// 05: continued
+  const A.a3([this.x = 'foo']); //# 03: continued
+  const A.a4(String this.x); //# 04: continued
+  const A.a5(String x) : this.x = x; //# 05: continued
   const A.a6(int x) : this.x = x;
 }
 
-var a1 = const A.a1(); /// 01: static type warning, checked mode compile-time error
-var a2 = const A.a2('foo'); /// 02: static type warning, checked mode compile-time error
-var a3 = const A.a3(); /// 03: static type warning, checked mode compile-time error
-var a4 = const A.a4('foo'); /// 04: static type warning, checked mode compile-time error
-var a5 = const A.a5('foo'); /// 05: static type warning, checked mode compile-time error
-var a6 = const A.a6('foo'); /// 06: static type warning, checked mode compile-time error
+var a1 = const A.a1(); //# 01: static type warning, checked mode compile-time error
+var a2 = const A.a2('foo'); //# 02: static type warning, checked mode compile-time error
+var a3 = const A.a3(); //# 03: static type warning, checked mode compile-time error
+var a4 = const A.a4('foo'); //# 04: static type warning, checked mode compile-time error
+var a5 = const A.a5('foo'); //# 05: static type warning, checked mode compile-time error
+var a6 = const A.a6('foo'); //# 06: static type warning, checked mode compile-time error
 
 main() {
-  print(a1); /// 01: continued
-  print(a2); /// 02: continued
-  print(a3); /// 03: continued
-  print(a4); /// 04: continued
-  print(a5); /// 05: continued
-  print(a6); /// 06: continued
+  print(a1); //# 01: continued
+  print(a2); //# 02: continued
+  print(a3); //# 03: continued
+  print(a4); //# 04: continued
+  print(a5); //# 05: continued
+  print(a6); //# 06: continued
 }