Add spec to test for disabled hidden field with disabled checkbox (cherry-pick from master)
Add spec to test for disabled hidden field with disabled checkbox (cherry-pick from master)

ryanfox1985/formtastic,crashlytics/formtastic,paulodiovani/formtastic,nishaya/formtastic,Baltazore/formtastic,ConferenceCloud/formtastic,Guestfolio/formtastic,justinfrench/formtastic,Guestfolio/formtastic,paulodiovani/formtastic,sideci-sample/sideci-sample-formtastic,thenthen8515/formtastic,Davidzhu001/formtastic,ryanfox1985/formtastic,nishaya/formtastic,justinfrench/formtastic,ryanfox1985/formtastic,EndingChaung/formtastic,mikz/formtastic,mikz/formtastic,justinfrench/formtastic,EndingChaung/formtastic,thenthen8515/formtastic,Davidzhu001/formtastic,ConferenceCloud/formtastic