* add index sample fp16 support

* remove fluid APIs in distributed_strategy.py and role_maker.py

* Revert "remove fluid APIs in distributed_strategy.py and role_maker.py"

This reverts commit 223bbee990d3bf69e252fc3c0f19e3873550a264.

* move load_inference_model to distributed

* fix origin develop codes diff

* move _endpoints_replacement

* delete line

* reset line

* add unittest case of load_inference_model

* fix unittest

* fix unittest

* fix coverage

* fix coverage