Add find_unused_parameters option to DeepSpeedEngine (#945)
* Add find_unused_parameters option
As unused parameters in modules may not be expected sometimes,
add an explicit error msg when it occurred and an option to avoid the error: https://github.com/microsoft/DeepSpeed/issues/707
* Add find_unused_parameters option
As unused parameters in modules may not be expected sometimes,
add an explicit error msg when it occurred and an option to avoid the error: https://github.com/microsoft/DeepSpeed/issues/707
* Fix syntax error
* Fix yapf error
* Fix yapf error
* Fix yapf error
* Fix yapf error
* Move stage2 find_unused_parameters to config file
* Add stage2 find_unused_parameters
* Add stage2 find_unused_parameters
* Add stage2_find_unused_parameters option
* Change error msg to reflect zero_optimization config change
* Fix yapf error
* Fix yapf errors
* Change find_unused_parameters option name
* Change find_unused_parameters option name
* Change find_unused_parameters option name
* Change find_unused_parameters option name
* Change find_unused_parameters option name
* Add UnusedParametersModel for test option find_unused_parameters
* Add unit test for stage2 find_unused_parameters
* Add cpu-adam compatible check
* Remove dups import
* Trim spaces
* Fix yapf errors
* Trim spaces
* Add False Positive test check
* Fix find_unused_parameters test
* Trim spaces
* Fix yapf error
