Implement backwards-compatible test for isActive
Implement backwards-compatible test for isActive

The isActive property is not available on earlier versions of iOS and
OS X. Implement a backwards-compatible test to fix unit tests running
on these system versions.

openaphid/PureLayout,bruce-wmm/PureLayout,k214k/PureLayout,neonaldo/PureLayout,PureWiki/PureLayout,Joneze/PureLayout,FiftyThree/PureLayout,liuyujing/PureLayout,lijie121210/PureLayout,adachic/PureLayout,yushuyi/PureLayout,smileyborg/PureLayout,ernestopino/PureLayout,TongKuo/PureLayout,foxswang/PureLayout,bruce-wmm/PureLayout,imjerrybao/PureLayout,Joneze/PureLayout,fhchina/PureLayout,FelixMLians/PureLayout,lijie121210/PureLayout,sandyway/PureLayout,pivotal-oscar/PureLayout,ppamorim/PureLayout,kompozer/PureLayout,k214k/PureLayout,adachic/PureLayout,pivotal-oscar/PureLayout,sandyway/PureLayout,abhilashreddykallepu/PureLayout,12207480/PureLayout,ppamorim/PureLayout,yushuyi/PureLayout,tangwei6423471/PureLayout,tangwei6423471/PureLayout,FiftyThree/PureLayout,neonaldo/PureLayout,cnbin/PureLayout,ernestopino/PureLayout,kompozer/PureLayout,12207480/PureLayout,Chunyulo/PureLayout,PureWiki/PureLayout,imjerrybao/PureLayout,fhchina/PureLayout,jiamaozheng/PureLayout,foxswang/PureLayout,openaphid/PureLayout,cnbin/PureLayout,abhilashreddykallepu/PureLayout,jiamaozheng/PureLayout,smileyborg/PureLayout,TongKuo/PureLayout,liuyujing/PureLayout,Chunyulo/PureLayout