CQ config: let CQ check CQ permissions.

CQ will only allow CL authors (owners in Gerrit) and V8 committers to trigger
CQ in Gerrit codereview. Thus, CQ voting restriction to just committers
can be lifted, letting every authenticated user attempt to trigger CQ.

R=machenbach@chromium.org,agable@chromium.org
BUG=641422,685318
NOTRY=True

Change-Id: Ied310a65277d6fefa44a9945cc780cb8fe827e03
Reviewed-on: https://chromium-review.googlesource.com/442124
Commit-Queue: Andrii Shyshkalov <tandrii@chromium.org>
Reviewed-by: Aaron Gable <agable@chromium.org>
Reviewed-by: Michael Achenbach <machenbach@chromium.org>
Cr-Commit-Position: refs/heads/master@{#43183}

infra/config/cq.cfg

@@ -19,6 +19,11 @@ verifiers {
     dry_run_access_list: "project-v8-tryjob-access"
   }
 
+  gerrit_cq_ability {
+    committer_list: "project-v8-committers"
+    dry_run_access_list: "project-v8-tryjob-access"
+  }
+
   tree_status {
     tree_status_url: "https://v8-status.appspot.com"
   }