This CL makes git-map-branches show CL status colors like git cl status
when -vvv is used. Statuses are fetched in parallel for speed.

BUG=379849

Review URL: https://codereview.chromium.org/938583002

git-svn-id: svn://svn.chromium.org/chrome/trunk/tools/depot_tools@294414 0039d316-1c4b-4281-b951-d872f2087c98