Add --issue option to 'git cl try-results'
Add --issue option to 'git cl try-results'

Sometimes I want to get try bot results without checking out the
relevant branch.

R=agable@chromium.org

Bug:
Change-Id: I89d118962ee37b10d95cf4044b61a0f2234b7e60
Reviewed-on: https://chromium-review.googlesource.com/710500
Commit-Queue: Stefan Zager <542cb5b73770f9741bae40d34cf7a192bc7ad2cc@chromium.org>
Reviewed-by: Andrii Shyshkalov <a30c74fa30536fe7ea81ed6dec202e35e149e1fd@chromium.org>

CoherentLabs/depot_tools,CoherentLabs/depot_tools