* Revert "set constant for loss"

This reverts commit 167933f6.

* Revert "remove workspace_handle"
test=develop
This reverts commit b4aca8ed.

* remove workspace_handle
test=develop

* set constant for loss
test=develop

test=develop

* Inception fusion operator.
* Support horizontal layer fusion in conv_fusion_op.
* Search conv algo strategy for variable-length input.
   search N times and cache the searched algos. For other input, choose the algo of input whose area is closest to this input.