git cl + git-numberer: add extra regression test case.
git cl + git-numberer: add extra regression test case.

R=76cc7f10de6bc994d83c4cb09072e4590b82b709@chromium.org
BUG=chromium:642493,672043

Change-Id: Ie50637d6e01e40ddd15dcdfc1430c9554fa82976
Reviewed-on: https://chromium-review.googlesource.com/418715
Reviewed-by: Michael Achenbach <76cc7f10de6bc994d83c4cb09072e4590b82b709@chromium.org>
Commit-Queue: Andrii Shyshkalov <a30c74fa30536fe7ea81ed6dec202e35e149e1fd@chromium.org>

CoherentLabs/depot_tools,CoherentLabs/depot_tools