Add support for //# sourceURL similar to deprecated //@ sourceURL one.

test/mjsunit/regress/regress-1853.js

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 84 matching lines @@
   }
 }
 
 Debug.setListener(listener);
 debugger;
 
 eval('function test1() {                \n' +
      '  assertFalse(test_break_1);      \n' +
      '  assertTrue(test_break_1);       \n' +
      '}                                 \n' +
-     '//@ sourceURL=testScriptOne');
+     '//# sourceURL=testScriptOne');
 
 eval('function test2() {                \n' +
      '  assertFalse(test_break_2);      \n' +
      '  assertTrue(test_break_2);       \n' +
      '}                                 \n' +
-     '//@ sourceURL=testScriptTwo');
+     '//# sourceURL=testScriptTwo');
 
 test1();
 test2();
 assertEquals(3, break_count);