Add unit test for mixed nesting of batch creation methods
Add unit test for mixed nesting of batch creation methods

Since both +[NSLayoutConstraint autoCreateAndInstallConstraints:] and
+[NSLayoutConstraint autoCreateConstraintsWithoutInstalling:] methods
rely on the same underlying data structure, add a unit test to ensure
that nesting them both together works correctly.

ernestopino/PureLayout,pivotal-oscar/PureLayout,bruce-wmm/PureLayout,FiftyThree/PureLayout,smileyborg/PureLayout,kompozer/PureLayout,FiftyThree/PureLayout,Chunyulo/PureLayout,pivotal-oscar/PureLayout,k214k/PureLayout,fhchina/PureLayout,Joneze/PureLayout,Chunyulo/PureLayout,bruce-wmm/PureLayout,yushuyi/PureLayout,neonaldo/PureLayout,imjerrybao/PureLayout,smileyborg/PureLayout,foxswang/PureLayout,neonaldo/PureLayout,yushuyi/PureLayout,abhilashreddykallepu/PureLayout,jiamaozheng/PureLayout,liuyujing/PureLayout,foxswang/PureLayout,fhchina/PureLayout,openaphid/PureLayout,TongKuo/PureLayout,jiamaozheng/PureLayout,abhilashreddykallepu/PureLayout,imjerrybao/PureLayout,lijie121210/PureLayout,adachic/PureLayout,tangwei6423471/PureLayout,ppamorim/PureLayout,lijie121210/PureLayout,k214k/PureLayout,sandyway/PureLayout,PureWiki/PureLayout,openaphid/PureLayout,Joneze/PureLayout,ppamorim/PureLayout,tangwei6423471/PureLayout,ernestopino/PureLayout,liuyujing/PureLayout,kompozer/PureLayout,cnbin/PureLayout,sandyway/PureLayout,adachic/PureLayout,TongKuo/PureLayout,PureWiki/PureLayout,cnbin/PureLayout