add the unhandled stack info to items with errors so that we propagate missing stack info for errors like SyntaxErrors which are buggy https://bugs.chromium.org/p/v8/issues/detail?id=2589
add the unhandled stack info to items with errors so that we propagate missing stack info for errors like SyntaxErrors which are buggy https://bugs.chromium.org/p/v8/issues/detail?id=2589

rollbar/rollbar.js