[CQ] Add experimental bots.

BUG=chromium:535160, chromium:561530
LOG=n
NOTRY=true

Review URL: https://codereview.chromium.org/1476133002

Cr-Commit-Position: refs/heads/master@{#32335}

infra/config/cq.cfg

@@ -44,6 +44,15 @@ verifiers {
       builders { name: "v8_win_compile_dbg" }
       builders { name: "v8_win_nosnap_shared_compile_rel" }
       builders { name: "v8_win_rel" }
+      builders {
+        name: "v8_win64_rel_ng"
+        experiment_percentage: 30
+      }
+      builders {
+        name: "v8_win64_rel_ng_triggered"
+        triggered: false
+        experiment_percentage: 30
+      }
     }
   }