Add `_.keys` unit test for `arguments` objects.
Add `_.keys` unit test for `arguments` objects.


Former-commit-id: dd90a9d3dc973a6ea8dce0c10ad511cce82097dd
shwaydogg/lodash,lzheng571/lodash,hitesh97/lodash,Jaspersoft/lodash,mjosh954/lodash,enng0227/lodash,BernhardRode/lodash,neouser99/lodash,schnerd/lodash,timruffles/lodash,justintung/lodash,krahman/lodash,shwaydogg/lodash,hafeez-syed/lodash,r14r/fork_javascript_lodash,huyinghuan/lodash,tonyonodi/lodash,r14r/fork_javascript_lodash,IveWong/lodash,xixilive/lodash,rlugojr/lodash,prawnsalad/lodash,steelsojka/lodash,jasnell/lodash,greyhwndz/lodash,developer-prosenjit/lodash,jshanson7/lodash,lekkas/lodash,mshoaibraja/lodash,r14r-work/fork_javascript_lodash,krrg/lodash,Andrey-Pavlov/lodash,Jaspersoft/lodash,xixilive/lodash,woldie/lodash,Moykn/lodash,mjosh954/lodash,dgoncalves1/lodash,tgriesser/lodash,Jaspersoft/lodash,ricardohbin/lodash,beaugunderson/lodash,transGLUKator/lodash,justintung/lodash,leolin1229/lodash,Andrey-Pavlov/lodash,mjosh954/lodash,gutenye/lodash,zhangguangyong/lodash,neouser99/lodash,zestia/lodash,tgriesser/lodash,naoina/lodash,samuelbeek/lodash,Lottid/lodash,AneesMohammed/lodash,woldie/lodash,samuelbeek/lodash,hafeez-syed/lodash,jzning-martian/lodash,Droogans/lodash,leolin1229/lodash,ror/lodash,krahman/lodash,IveWong/lodash,Droogans/lodash,julianocomg/lodash,jasnell/lodash,bnicart/lodash,MaxPRafferty/lodash,gutenye/lodash,hitesh97/lodash,rlugojr/lodash,jacwright/lodash,ror/lodash,hafeez-syed/lodash,zestia/lodash,lekoaf/lodash,tquetano-r7/lodash,shwaydogg/lodash,PhiLhoSoft/lodash,huyinghuan/lodash,lekkas/lodash,lekkas/lodash,tejokumar/lodash,andersonaguiar/lodash,chrootsu/lodash,krahman/lodash,Xotic750/lodash,naoina/lodash,jzning-martian/lodash,tejokumar/lodash,jzning-martian/lodash,timruffles/lodash,polarbird/lodash,polarbird/lodash,rtorr/lodash,krrg/lodash,enng0227/lodash,Moykn/lodash,therebelbeta/lodash,af7/lodash,reggi/lodash,woldie/lodash,enng0227/lodash,julianocomg/lodash,huyinghuan/lodash,jasnell/lodash,nbellowe/lodash,developer-prosenjit/lodash,andersonaguiar/lodash,krrg/lodash,MaxPRafferty/lodash,AndBicScadMedia/lodash,boneskull/lodash,lzheng571/lodash,leolin1229/lodash,dgoncalves1/lodash,tonyonodi/lodash,imjerrybao/lodash,codydaig/lodash,nbellowe/lodash,imjerrybao/lodash,javiosyc/lodash,boneskull/lodash,ror/lodash,codydaig/lodash,julianocomg/lodash,r14r-work/fork_javascript_lodash,greyhwndz/lodash,bnicart/lodash,xiwc/lodash,stewx/lodash,Xotic750/lodash,r14r-work/fork_javascript_lodash,Xotic750/lodash,af7/lodash,joshuaprior/lodash,rtorr/lodash,xiwc/lodash,chrootsu/lodash,nsamarcos/lodash,Lottid/lodash,felixshu/lodash,nsamarcos/lodash,dgoncalves1/lodash,Moykn/lodash,javiosyc/lodash,studiowangfei/lodash,studiowangfei/lodash,joshuaprior/lodash,ajefremovs/lodash,jacwright/lodash,BernhardRode/lodash,studiowangfei/lodash,lekoaf/lodash,BernhardRode/lodash,greyhwndz/lodash,AneesMohammed/lodash,zhangguangyong/lodash,phillipalexander/lodash,PhiLhoSoft/lodash,schnerd/lodash,prawnsalad/lodash,tquetano-r7/lodash,af7/lodash,msmorgan/lodash,mshoaibraja/lodash,phillipalexander/lodash,lzheng571/lodash,jshanson7/lodash,Droogans/lodash,PhiLhoSoft/lodash,r14r/fork_javascript_lodash,reggi/lodash,benweet/lodash,developer-prosenjit/lodash,MaxPRafferty/lodash,polarbird/lodash,justintung/lodash,rtorr/lodash,xixilive/lodash,transGLUKator/lodash,mshoaibraja/lodash,ricardohbin/lodash,AndBicScadMedia/lodash,reggi/lodash,prawnsalad/lodash,tejokumar/lodash,benweet/lodash,codydaig/lodash,ajefremovs/lodash,steelsojka/lodash,phillipalexander/lodash,jacwright/lodash,javiosyc/lodash,benweet/lodash,msmorgan/lodash,felixshu/lodash,zestia/lodash,stewx/lodash,jshanson7/lodash,therebelbeta/lodash,imjerrybao/lodash,stewx/lodash,samuelbeek/lodash,Andrey-Pavlov/lodash,therebelbeta/lodash,youprofit/lodash,schnerd/lodash,andersonaguiar/lodash,nsamarcos/lodash,youprofit/lodash,timruffles/lodash,beaugunderson/lodash,Lottid/lodash,zhangguangyong/lodash,youprofit/lodash,gdi2290/lodash,lekoaf/lodash,AneesMohammed/lodash,felixshu/lodash,naoina/lodash,ricardohbin/lodash,hitesh97/lodash,chrootsu/lodash,gutenye/lodash,tquetano-r7/lodash,tgriesser/lodash,xiwc/lodash,IveWong/lodash,joshuaprior/lodash,gdi2290/lodash,neouser99/lodash,ajefremovs/lodash,AndBicScadMedia/lodash,bnicart/lodash,transGLUKator/lodash,nbellowe/lodash