Takes the script offset into account when obtaining the column of the message.

R=jochen@chromium.org,yangguo@chromium.org

Review URL: https://codereview.chromium.org/1231663007

Cr-Commit-Position: refs/heads/master@{#29761}

src/messages.js

@@ -542,7 +542,7 @@ utils.SetUpLockedPrototype(SourceSlice,
 function GetPositionInLine(message) {
   var script = %MessageGetScript(message);
   var start_position = %MessageGetStartPosition(message);
-  var location = script.locationFromPosition(start_position, false);
+  var location = script.locationFromPosition(start_position, true);
   if (location == null) return -1;
   return location.column;
 }