clean clang format errors and cpplint errors

add some test cases for histogram summary operator

Merge pull request !333 from jiangzhiwen/dataset/skip

Merge pull request !434 from h.farahat/multi_itr_bug

Add new test cases

Merge pull request !395 from zjun/fix_oplib_codexx

Merge pull request !414 from liubuyu/dev_lby

Merge pull request !350 from lianliguang/chang-tuple-output-to-make-tuple

Merge pull request !429 from chenfei/expand-tuple-output-of-node-when-set-child-graph-input

Merge pull request !385 from Xiaoda/modify-communicaiton-cost-of-operators-and-redistribution

Merge pull request !422 from ms_yan/Generator_distri

Merge pull request !421 from ghzl/fix-no-wrap-in-ge-bankend-in-train

Merge pull request !317 from huanghui/derelu_fusion_pass

Merge pull request !415 from jjfeing/master

Merge pull request !412 from YuJianfeng/master

Merge pull request !416 from xiefangqi/br_fix_apply_comment

Merge pull request !411 from Simson/push-to-opensource

Merge pull request !402 from yangzhenzhang/square

Merge pull request !417 from anzhengqi/fix-commit-format-error

Merge pull request !408 from ZhouFeng/cmake317-windows

Merge pull request !413 from chenjianping/eliminate-securec-warning

Merge pull request !383 from zhaozhenlong/cell/psnr

Merge pull request !286 from wangqiuliang/resolve-pynative-operator-issue

Merge pull request !378 from h.farahat/multi_itr

-- Iterator list is keeping  all created iterators wihtout cleaning them up
-- alter tree modifies the original.