Support error handling in forked threads (#14523)
Summary:
Save error info in the future for parent thread to pick up. Throw the error
when the thread is the root thread.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/14523
Differential Revision: D13251756
Pulled By: highker
fbshipit-source-id: b40f9a45665e1a934743f131ec5e8bad5622ce67
