Make test_proper_exit more robust (#16249)
Summary:
1. Improve error message for better debugging info
2. Increase timeout
3. Also apply the windows worker failure detection mechanism on non-Windows platforms, for better robustness
Attempt to fix #14501
cc ezyang
Pull Request resolved: https://github.com/pytorch/pytorch/pull/16249
Differential Revision: D13784702
Pulled By: ezyang
fbshipit-source-id: 09a7cff83ab9edce561ed69f9fb555ab35d1275f
