Don't double check trace origin in ExceptionWrapper#traces

If a trace isn't an application one, then it comes from a framework.
That's the [definition][] of framework trace. We can speed up the traces
generation if we don't double check that.

[definition]: https://github.com/gsamokovarov/rails/blob/ff1902789d45190dd298b65342699d6043dd8ef2/activesupport/lib/active_support/backtrace_cleaner.rb#L99-L101