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)

2. remove lod check in reshape op
test=develop

* 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

* fix broadcast with mp mode

* polish code test=develop

* fix bcast strategy test=develop

* fic cpplint test=develop

* fix py3 failed test=develop

* fix comment test=develop

* update comment test=develop

* remove concast_cast and refactor code test=develop

* reduce flag use test=develop

test=develop

test=develop

test=develop

* Revert "Revert "Add Event for TensorCopy" (#16022)"

This reverts commit e2da3a5b.

* use default stream
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

* add parallel graph dist test=develop

* update test=develop

* update style test=develop

* add parallel graph dist test=develop

* update test=develop

* update style test=develop

test=develop

* add ir memory optimize test case for IfElse op, test=develop

* fix some unitttest failure by force using the python memory_optimize, test=develop

* tweak comments, test=develop

* fix unittest, test=develop

* fix unittest, test=develop

test=develop

test=develop

* add ir memory optimize test case for IfElse op, test=develop

* fix some unitttest failure by force using the python memory_optimize, test=develop

* tweak comments, test=develop

* fix unittest, test=develop

* fix unittest, test=develop

test=develop

* Revert "Add Event for TensorCopy (#15953)"

This reverts commit 7235fd66.
test=develop

* fix CI
test=develop

* Unified ParallelExecutor and Compiler

Add Event for TensorCopy 

* add op name in check nan/inf, test=develop

test=develop

test=develop

test=develop

test=develop

* staged.

* polish code

* polish code. test=develop

* polish code. test=develop

* api change. test=develop

* fix default value. test=develop

* fix default value. test=develop

test=develop

test=develop