Add debug bots to the default list of trybots.

The updated list of bots matches the one defined in commit-queue:
<http://src.chromium.org/viewvc/chrome/trunk/tools/commit-queue/projects.py?revision=240164#l194>

BUG=none

Review URL: https://codereview.chromium.org/115043002

git-svn-id: svn://svn.chromium.org/blink/trunk@163931 bbb929c8-8fbe-4397-9dbb-9b2b20218538