* Add simplify_with_basic_ops_pass to replace dropout_op with scale_op when is_test is true.
test=develop

* Delete dropout_op directly when upscale_in_train is true.
test=develop

* Improve the debug string, adding the print of op_desc information.

* Fix the case when dropout's input x is reused as the next op's output.

* Add the pass to inference.
test=develop

* Change the log level.
test=develop

* Add unittest for inplace case.

* Add comment to explain the pass.

* Apply the pass for CPU inference.
test=develop

* Fix the typo.
test=develop

* Add the check of AttrType.
test=develop