Commit 385d11e2ed moved the logic
that performs report formatting into the reporters themselves. But
it also contained a logic change to the formatting.
Previously, if an item was not mergeable, it was reported without
a job list, regardless if the merge-failure or standard failure
reporter was used. With that change, if a pipeline specified a
merge-failure message reporter, it would not format the job list,
but if no merge-failure reporter was supplied, and the standard
failure reporter was used, the standard failure reporter would not
check whether a merge-failure happened and instead always try to
format the job list.
Change-Id: If65d4f64d6558a544d3d0c2cc0b32ad7786a6bcd
f760f0e49f