* fix remote large update core

* wip

* working version

* fix style check

* fix style check

* update style check

  1. It's no problem with relative precision 1e-3 when testing several times in my local machine.
  2. But the testing failed with 1e-2 in the TeamCity, and only one value's relative precision is over 1e-2. So tune it to 4e-2

related codes in Paddle core.

to create a gradient machine for inference using merged model with parameters
which is genearted by `paddle merge_model`.