Convert blink presubmit to use new multiple-tryserver-compatible protocol

BUG=334892
R=dpranke@chromium.org, jamesr@chromium.org

Review URL: https://codereview.chromium.org/195383003

git-svn-id: svn://svn.chromium.org/blink/trunk@168937 bbb929c8-8fbe-4397-9dbb-9b2b20218538