[CQ] Experiment: Add blink trybots to CQ.

infra/config/cq.cfg

Index: infra/config/cq.cfg
diff --git a/infra/config/cq.cfg b/infra/config/cq.cfg
index 2a98e767988b2ed2deb9f7e3da67de9166edf31a..ea289b2bfbc68b4cd918fd04ed91c171d5b2e8ce 100644
--- a/infra/config/cq.cfg
+++ b/infra/config/cq.cfg
@@ -53,6 +53,13 @@ verifiers {
         triggered_by: "v8_win_rel_ng"
       }
     }
+    buckets {
+      name: "tryserver.blink"
+      builders {
+        name: "linux_blink_rel"
+        experiment_percentage: 20
+      }
+    }
   }
 
   sign_cla {}