Fix warnings_checker.dart handling of multitests

tests/language/ref_before_declaration_test.dart

Index: tests/language/ref_before_declaration_test.dart
diff --git a/tests/language/ref_before_declaration_test.dart b/tests/language/ref_before_declaration_test.dart
index 677f6bee2a56d0cf3e4326b0944b0b1316bd42d1..9a6c2b556cdc956e897d803895f6ac4e6fe3686a 100644
--- a/tests/language/ref_before_declaration_test.dart
+++ b/tests/language/ref_before_declaration_test.dart
@@ -18,7 +18,7 @@ class C {
 
   void test1() {
   	use(f);  // Refers to instance field f.
-    var f = 'A shut mouth gathers no foot.'; // /// 00: compile-time error
+    var f = 'A shut mouth gathers no foot.'; // //# 00: compile-time error
   }
 
   void test2() {
@@ -26,7 +26,7 @@ class C {
       use(f);  // Refers to instance field f.
   	}
 
-    var f = 'When chemists die, they barium.'; // /// 01: compile-time error
+    var f = 'When chemists die, they barium.'; // //# 01: compile-time error
     if (true) {
       var f = 1; // ok, shadows outer f and instance field f.
     }
@@ -37,19 +37,19 @@ class C {
       use(x);  // Refers to top-level x.
       use(y);  // Refers to top-level y.
     }
-    final x = "I have not yet begun to procrastinate."; // /// 02: compile-time error
-    const y = "Honk if you like peace and quiet!"; // /// 03: compile-time error
+    final x = "I have not yet begun to procrastinate."; // //# 02: compile-time error
+    const y = "Honk if you like peace and quiet!"; // //# 03: compile-time error
   }
 
   void test4() {
     void Q() {
       P();  // Refers to non-existing top-level function P
     }
-    void P() { // /// 06: compile-time error
-      Q(); //     /// 06: continued
-    } //          /// 06: continued
+    void P() { // //# 06: compile-time error
+      Q(); //     //# 06: continued
+    } //          //# 06: continued
 
-    Function f = () {x = f;}; // /// 07: compile-time error
+    Function f = () {x = f;}; // //# 07: compile-time error
   }
 
   test() {
@@ -62,12 +62,12 @@ class C {
 
 void testTypeRef() {
   String s = 'Can vegetarians eat animal crackers?';
-  var String = "I distinctly remember forgetting that."; // /// 04: compile-time error
+  var String = "I distinctly remember forgetting that."; // //# 04: compile-time error
 }
 
 void testLibPrefix() {
   var pie = math.PI;
-  final math = 0; // /// 05: compile-time error
+  final math = 0; // //# 05: compile-time error
 }