* support empty tensor

* Move Select to concurrency.py; incorporate outputs

* CLang formatting for concurrency

* Remove extra bracket - formatting fix - 3

* Comment fix

* Temporarily fix bug for backward tanspiler when using parallel_do operator.

* Fix bug for backward tanspiler when using parallel_do operator

Fix CI.

removed diagnostic

- Added Unit tests for Softmax MKLDNN Forward

Added fix for div by 0 to happen in cross_entropy backward

Conflicts:
	paddle/fluid/operators/CMakeLists.txt

- Cosmetic fixes to SoftMax MKLDNN fluid operator

Added misssing softmax fluid operator file

Disabled MKLDNN softmax operator by default

Fix to softmax op unittest merge

clang_formater fixes

clang_formatter fixes

- Name changing of softmax mkldnn operator to maintin consistency
  across codebase

- updated comment

fix to comment

Add an argument in Executor.Run to allow users to choose whether to create and destroy variables every time. (#9242)

optimize executor.run