Revert "Mark builders with Win10 GCE slaves as experimental."

This reverts commit d979063b.

Reason for revert: Reasonable pending times, right now; let these builders back on the CQ while we keep any eye on things and work on a more permanent solution.

Original change's description:
> Mark builders with Win10 GCE slaves as experimental.
> 
> Bug: 819355
> Change-Id: Ib242933a5a3d1cf4d03edac0cb4b4e6be468b12d
> Reviewed-on: https://chromium-review.googlesource.com/952777
> Reviewed-by: John Budorick <jbudorick@chromium.org>
> Reviewed-by: smut <smut@google.com>
> Cr-Commit-Position: refs/heads/master@{#541326}

TBR=smut@google.com,jchinlee@chromium.org,jbudorick@chromium.org

Change-Id: I827b55a796c8e41f273552a9ea42e222b59b8d4d
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: 819355
Reviewed-on: https://chromium-review.googlesource.com/953030Reviewed-by: Jao-ke Chin-Lee <jchinlee@chromium.org>
Commit-Queue: Jao-ke Chin-Lee <jchinlee@chromium.org>
Cr-Commit-Position: refs/heads/master@{#541513}

infra/config/branch/cq.cfg

@@ -156,15 +156,11 @@ verifiers {
       }
       builders {
         name: "win7_chromium_rel_ng"
-        # TODO(jchinlee): uncomment when crbug/819355 is fixed.
-        #equivalent_to { bucket: "luci.chromium.try" percentage: 0 }
-        experiment_percentage: 100
+        equivalent_to { bucket: "luci.chromium.try" percentage: 0 }
       }
       builders {
         name: "win10_chromium_x64_rel_ng"
-        # TODO(jchinlee): uncomment when crbug/819355 is fixed.
-        #equivalent_to { bucket: "luci.chromium.try" percentage: 0 }
-        experiment_percentage: 100
+        equivalent_to { bucket: "luci.chromium.try" percentage: 0 }
       }
       builders {
         name: "win_chromium_compile_dbg_ng"