Fix the numerical gradient checker in `test_utils` (#3663)
Fix the numerical gradient checker in `test_utils` (#3663)

Remove unnecessary `ascontiguous`

Fix docstring + Add assert_almost_equal

fix lint
tlby/mxnet,vikingMei/mxnet,xcgoner/dist-mxnet,pluskid/mxnet,DR08/mxnet,xcgoner/dist-mxnet,rahul003/mxnet,Ldpe2G/mxnet,kkk669/mxnet,gautamkmr/incubator-mxnet,danithaca/mxnet,tlby/mxnet,ptrendx/mxnet,Guneet-Dhillon/mxnet,Mega-DatA-Lab/mxnet,crazy-cat/incubator-mxnet,arank/mxnet,jamesliu/mxnet,danithaca/mxnet,xcgoner/dist-mxnet,stefanhenneking/mxnet,dmlc/mxnet,likelyzhao/mxnet,CodingCat/mxnet,sergeykolychev/mxnet,Mega-DatA-Lab/mxnet,yajiedesign/mxnet,weleen/mxnet,tornadomeet/mxnet,tornadomeet/mxnet,vikingMei/mxnet,likelyzhao/mxnet,CodingCat/mxnet,nicklhy/mxnet,reminisce/mxnet,wangyum/mxnet,luoyetx/mxnet,stefanhenneking/mxnet,stefanhenneking/mxnet,saurabh3949/mxnet,madjam/mxnet,hesseltuinhof/mxnet,lxn2/mxnet,szha/mxnet,piiswrong/mxnet,hotpxl/mxnet,gautamkmr/incubator-mxnet,arank/mxnet,weleen/mxnet,weleen/mxnet,antoan2/incubator-mxnet,coder-james/mxnet,danithaca/mxnet,ForkedReposBak/mxnet,ForkedReposBak/mxnet,tornadomeet/mxnet,jennyzhang0215/incubator-mxnet,stefanhenneking/mxnet,LinkHS/incubator-mxnet,TuSimple/mxnet,stefanhenneking/mxnet,Northrend/mxnet,jennyzhang0215/incubator-mxnet,hpi-xnor/BMXNet,lxn2/mxnet,ykim362/mxnet,dmlc/mxnet,hotpxl/mxnet,indhub/mxnet,CodingCat/mxnet,fullfanta/mxnet,yajiedesign/mxnet,jiajiechen/mxnet,DickJC123/mxnet,TuSimple/mxnet,formath/mxnet,coder-james/mxnet,jamesliu/mxnet,jermainewang/mxnet,saurabh3949/mxnet,yajiedesign/mxnet,rishita/mxnet,pluskid/mxnet,TuSimple/mxnet,EvanzzzZ/mxnet,hotpxl/mxnet,pluskid/mxnet,navrasio/mxnet,CodingCat/mxnet,navrasio/mxnet,piiswrong/mxnet,ForkedReposBak/mxnet,solin319/incubator-mxnet,ptrendx/mxnet,sxjscience/mxnet,smolix/incubator-mxnet,eric-haibin-lin/mxnet,hesseltuinhof/mxnet,DR08/mxnet,reminisce/mxnet,ZihengJiang/mxnet,leezu/mxnet,mbaijal/incubator-mxnet,Mega-DatA-Lab/mxnet,precedenceguo/mxnet,yuruofeifei/mxnet,kevinthesun/mxnet,wangyum/mxnet,jennyzhang0215/incubator-mxnet,navrasio/mxnet,arikpoz/mxnet,thirdwing/mxnet,reminisce/mxnet,hpi-xnor/BMXNet,precedenceguo/mxnet,LinkHS/incubator-mxnet,apaleyes/mxnet,Northrend/mxnet,crazy-cat/incubator-mxnet,fullfanta/mxnet,jiajiechen/mxnet,madjam/mxnet,hpi-xnor/BMXNet,CodingCat/mxnet,hesseltuinhof/mxnet,DickJC123/mxnet,hpi-xnor/BMXNet,LinkHS/incubator-mxnet,arank/mxnet,sxjscience/mxnet,coder-james/mxnet,hotpxl/mxnet,tornadomeet/mxnet,solin319/incubator-mxnet,apaleyes/mxnet,ShownX/incubator-mxnet,madjam/mxnet,smolix/incubator-mxnet,precedenceguo/mxnet,lxn2/mxnet,piiswrong/mxnet,EvanzzzZ/mxnet,antoan2/incubator-mxnet,yajiedesign/mxnet,fullfanta/mxnet,antoan2/incubator-mxnet,yajiedesign/mxnet,weleen/mxnet,fullfanta/mxnet,TuSimple/mxnet,vikingMei/mxnet,nicklhy/mxnet,rishita/mxnet,wangyum/mxnet,weleen/mxnet,stefanhenneking/mxnet,thirdwing/mxnet,kkk669/mxnet,Prasad9/incubator-mxnet,Prasad9/incubator-mxnet,apaleyes/mxnet,DR08/mxnet,jennyzhang0215/incubator-mxnet,apache/incubator-mxnet,mbaijal/incubator-mxnet,xcgoner/dist-mxnet,stefanhenneking/mxnet,TuSimple/mxnet,szha/mxnet,Ldpe2G/mxnet,thirdwing/mxnet,formath/mxnet,indhub/mxnet,zhreshold/mxnet,jiajiechen/mxnet,Mega-DatA-Lab/mxnet,sergeykolychev/mxnet,apaleyes/mxnet,ptrendx/mxnet,tornadomeet/mxnet,dmlc/mxnet,danithaca/mxnet,apaleyes/mxnet,CodingCat/mxnet,kevinthesun/mxnet,DickJC123/mxnet,navrasio/mxnet,zhreshold/mxnet,TuSimple/mxnet,gautamkmr/incubator-mxnet,szha/mxnet,EvanzzzZ/mxnet,jiajiechen/mxnet,ForkedReposBak/mxnet,jamesliu/mxnet,wangyum/mxnet,dmlc/mxnet,smolix/incubator-mxnet,Northrend/mxnet,crazy-cat/incubator-mxnet,yuruofeifei/mxnet,jennyzhang0215/incubator-mxnet,vikingMei/mxnet,stefanhenneking/mxnet,arank/mxnet,larroy/mxnet,zhreshold/mxnet,leezu/mxnet,arikpoz/mxnet,eric-haibin-lin/mxnet,ZihengJiang/mxnet,lxn2/mxnet,jermainewang/mxnet,wangyum/mxnet,hotpxl/mxnet,indhub/mxnet,hesseltuinhof/mxnet,ykim362/mxnet,ForkedReposBak/mxnet,leezu/mxnet,fullfanta/mxnet,zhreshold/mxnet,dmlc/mxnet,apaleyes/mxnet,Ldpe2G/mxnet,saurabh3949/mxnet,rahul003/mxnet,jamesliu/mxnet,vikingMei/mxnet,jiajiechen/mxnet,ZihengJiang/mxnet,ykim362/mxnet,crazy-cat/incubator-mxnet,weleen/mxnet,precedenceguo/mxnet,solin319/incubator-mxnet,zhreshold/mxnet,fullfanta/mxnet,Guneet-Dhillon/mxnet,Northrend/mxnet,solin319/incubator-mxnet,ShownX/incubator-mxnet,gautamkmr/incubator-mxnet,Guneet-Dhillon/mxnet,kkk669/mxnet,thirdwing/mxnet,tlby/mxnet,szha/mxnet,crazy-cat/incubator-mxnet,yuruofeifei/mxnet,jennyzhang0215/incubator-mxnet,tornadomeet/mxnet,zhreshold/mxnet,ForkedReposBak/mxnet,thirdwing/mxnet,EvanzzzZ/mxnet,ForkedReposBak/mxnet,jiajiechen/mxnet,smolix/incubator-mxnet,ykim362/mxnet,hesseltuinhof/mxnet,hotpxl/mxnet,mbaijal/incubator-mxnet,formath/mxnet,leezu/mxnet,pluskid/mxnet,nicklhy/mxnet,nicklhy/mxnet,saurabh3949/mxnet,jermainewang/mxnet,madjam/mxnet,jiajiechen/mxnet,precedenceguo/mxnet,danithaca/mxnet,indhub/mxnet,weleen/mxnet,rishita/mxnet,crazy-cat/incubator-mxnet,eric-haibin-lin/mxnet,crazy-cat/incubator-mxnet,Prasad9/incubator-mxnet,formath/mxnet,larroy/mxnet,thirdwing/mxnet,ShownX/incubator-mxnet,LinkHS/incubator-mxnet,Mega-DatA-Lab/mxnet,precedenceguo/mxnet,piiswrong/mxnet,solin319/i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