Remove Chromium Win experiment as it is not used

TBR=machenbach@chromium.org

No-Try: true
Change-Id: I97dcb68e243aaaac4e103c862a0c28a41fe6553b
Reviewed-on: https://chromium-review.googlesource.com/864264Reviewed-by: Sergiy Byelozyorov <sergiyb@chromium.org>
Commit-Queue: Sergiy Byelozyorov <sergiyb@chromium.org>
Cr-Commit-Position: refs/heads/master@{#50543}

infra/config/cq.cfg

@@ -117,13 +117,6 @@ verifiers {
         triggered_by: "v8_win_rel_ng"
       }
     }
-    buckets {
-      name: "master.tryserver.chromium.win"
-      builders {
-        name: "win_chromium_compile_dbg_ng"
-        experiment_percentage: 100
-      }
-    }
   }
 
   sign_cla {}