[Notification] Fix StatusNotification postedTime property
[Notification] Fix StatusNotification postedTime property

TCT Tests changed comparison from 'null' to 'undefined'

pk-sam/tizen-extensions-crosswalk,pk-sam/tizen-extensions-crosswalk,crosswalk-project/tizen-extensions-crosswalk,paritosh-in/tizen-extensions-crosswalk,crosswalk-project/tizen-extensions-crosswalk,pk-sam/tizen-extensions-crosswalk,pk-sam/tizen-extensions-crosswalk,paritosh-in/tizen-extensions-crosswalk,paritosh-in/tizen-extensions-crosswalk,hgl888/tizen-extensions-crosswalk,hgl888/tizen-extensions-crosswalk,crosswalk-project/tizen-extensions-crosswalk,paritosh-in/tizen-extensions-crosswalk,crosswalk-project/tizen-extensions-crosswalk,hgl888/tizen-extensions-crosswalk,pk-sam/tizen-extensions-crosswalk,hgl888/tizen-extensions-crosswalk,paritosh-in/tizen-extensions-crosswalk,hgl888/tizen-extensions-crosswalk,crosswalk-project/tizen-extensions-crosswalk,hgl888/tizen-extensions-crosswalk,pk-sam/tizen-extensions-crosswalk,crosswalk-project/tizen-extensions-crosswalk,paritosh-in/tizen-extensions-crosswalk