[V8] Fix messages GetPositionInLine method

src/messages.js

 // Copyright 2012 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.
 
 // -------------------------------------------------------------------
 
 var kMessages = {
   // Error
   cyclic_proto:                  ["Cyclic __proto__ value"],
   code_gen_from_strings:         ["%0"],
@@ skipping 761 matching lines @@
 
 
 // Returns the offset of the given position within the containing
 // line.
 function GetPositionInLine(message) {
   var script = %MessageGetScript(message);
   var start_position = %MessageGetStartPosition(message);
   var location = script.locationFromPosition(start_position, false);
   if (location == null) return -1;
   location.restrict();
-  return start_position - location.start;
+  return location.column;
 }
 
 
 function GetStackTraceLine(recv, fun, pos, isGlobal) {
   return new CallSite(recv, fun, pos, false).toString();
 }
 
 // ----------------------------------------------------------------------------
 // Error implementation
 
@@ skipping 534 matching lines @@
 function SetUpStackOverflowBoilerplate() {
   var boilerplate = MakeRangeError('stack_overflow', []);
 
   %DefineAccessorPropertyUnchecked(
       boilerplate, 'stack', StackTraceGetter, StackTraceSetter, DONT_ENUM);
 
   return boilerplate;
 }
 
 var kStackOverflowBoilerplate = SetUpStackOverflowBoilerplate();