Revert "Removed support deprecated (//@|/*@) source(URL|MappingURL)="

test/mjsunit/regress/regress-crbug-481896.js

 // Copyright 2015 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 // Flags: --expose-debug-as debug
 
 function static() {
   print("> static");  // Break
 }
 
@@ skipping 11 matching lines @@
     exception = e;
   }
 }
 
 Debug.setListener(listener);
 
 function install() {
   eval("this.dynamic = function dynamic() { \n" +
        "  print(\"> dynamic\");  // Break\n" +
        "}\n" +
-       "//# sourceURL=dynamicScript");
+       "//@ sourceURL=dynamicScript");
 }
 
 install();
 
 var scripts = Debug.scripts();
 var dynamic_script;
 var static_script;
 for (var script of scripts) {
   if (script.source_url == "dynamicScript") dynamic_script = script;
   if (script.source_url == "staticScript") static_script = script;
 }
 
 Debug.setScriptBreakPointById(dynamic_script.id, 1);
 Debug.setScriptBreakPointById(static_script.id, 7);
 
 dynamic();
 static();
 
 Debug.setListener(null);
 
 assertNull(exception);
 assertEquals(2, break_count);
 
-//# sourceURL=staticScript
+//@ sourceURL=staticScript