Added a `createCallAcknowledgeOperationStatus()` test helper.
Added a `createCallAcknowledgeOperationStatus()` test helper.

Review: https://reviews.apache.org/r/66057/

gsantovena/mesos,kaysoky/mesos,Gilbert88/mesos,gsantovena/mesos,jpeach/mesos,andschwa/mesos,andschwa/mesos,abudnik/mesos,jpeach/mesos,andschwa/mesos,chhsia0/mesos,jpeach/mesos,dforsyth/mesos,Gilbert88/mesos,reneploetz/mesos,asamerh4/mesos,kaysoky/mesos,abudnik/mesos,kaysoky/mesos,andschwa/mesos,chhsia0/mesos,kaysoky/mesos,chhsia0/mesos,abudnik/mesos,Gilbert88/mesos,abudnik/mesos,dforsyth/mesos,jpeach/mesos,jpeach/mesos,asamerh4/mesos,andschwa/mesos,dforsyth/mesos,chhsia0/mesos,gsantovena/mesos,abudnik/mesos,chhsia0/mesos,Gilbert88/mesos,reneploetz/mesos,gsantovena/mesos,jpeach/mesos,kaysoky/mesos,Gilbert88/mesos,asamerh4/mesos,abudnik/mesos,dforsyth/mesos,chhsia0/mesos,Gilbert88/mesos,reneploetz/mesos,andschwa/mesos,asamerh4/mesos,andschwa/mesos,reneploetz/mesos,gsantovena/mesos,dforsyth/mesos,asamerh4/mesos,asamerh4/mesos,gsantovena/mesos,abudnik/mesos,kaysoky/mesos,Gilbert88/mesos,dforsyth/mesos,jpeach/mesos,gsantovena/mesos,reneploetz/mesos,asamerh4/mesos,dforsyth/mesos,reneploetz/mesos,kaysoky/mesos,chhsia0/mesos,reneploetz/mesos