* Add enabling quantization

test=develop

* remove unused (here) function

test=develop

test=develop

test=develop

* Add cpu_quantize_placement_pass for C-API quantization

test=develop

* added a comment on required pass attributes

test=develop

test=develop

test=develop

test=develop

* Add cpu_quantize_pass for C-API quantization

test=develop

* add cpu_quantize_pass test

* fix lint: add include memory unorderd_map and unordered_set

test=develop

* fuse_relu 1

test=develop

* tuned 2 without squash

* fixes

test=develop

* remove unused vars

test=develop

* refactored

test=develop

* fix lint c-style cast -> C++ style cast

test=develop

* remove QuantMax and c style casts

test=develop

* last usage of QuantMax removed

test=develop

* Fix Analysis Predictor UT

Check if memory_optimize_pass has already been added
to the analysis config before adding a new one, so
that it is not added multiple times.
test=develop

* change map to unordered_map

fix the forgotten part of cpu_quantize_pass_tester.cc

test=develop

* removed quantized attribute

* fixed cpu_quantize_pass_tester and op attr comments

test=develop

* removed redundant line

test=debug

* removed gmock

test=develop

* fix after merge

test=develop

* Support Sync Batch Norm.
* Note, do not enable it in one device.

Usage:

build_strategy = fluid.BuildStrategy()
build_strategy.sync_batch_norm = True
binary = fluid.compiler.CompiledProgram(tp).with_data_parallel(
        loss_name=loss_mean.name,
        build_strategy=build_strategy)

* Add cpu_quantize_squash_pass for C-API quantization

test=develop

* add cpu_quantize_squash_pass teste

* fix lint: add include memory unorderd_map and unordered_set

test=develop

* lint fix 2

* fixes

test=develop

* refactored

test=develop

* fix windows ci

test=develop

test=develop

* Fix the node's sort issue when the graph is changed.

test=develop

* Clean code

test=develop

test=develop

test=develop

* Fix the node's sort issue when the graph is changed.

test=develop

* Clean code

test=develop

test=develop

test=develop

test=develop

test=develop

test=develop

test=develop

test=develop

* MKL-DNN: Add test for conv bias fuse pass

test=develop

* Remove const cast from Conv Bias Pass Test

* Add conv with bias test case for conv+bias fuse ut

test=develop

test=develop

and #pragma once in edited headers

add #include<string> in edited headers

test=develop

* fix warnings

test=develop

* fix enforce test

test=develop

test=develop