[CQ] Add coverage bot to cq experiment.

infra/config/cq.cfg

Index: infra/config/cq.cfg
diff --git a/infra/config/cq.cfg b/infra/config/cq.cfg
index fbf090bb595acc1a1983fcb10fdef813a6d2700d..b29aba7186b3d00063602f6d1734ae46f6111408 100644
--- a/infra/config/cq.cfg
+++ b/infra/config/cq.cfg
@@ -65,13 +65,14 @@ verifiers {
         name: "v8_win_rel_ng_triggered"
         triggered_by: "v8_win_rel_ng"
       }
-    }
-    buckets {
-      name: "tryserver.v8"
       builders {
         name: "v8_linux_blink_rel"
         experiment_percentage: 20
       }
+      builders {
+        name: "v8_linux64_sanitizer_coverage_rel"
+        experiment_percentage: 30
+      }
     }
   }