Ramp win10_chromium_x64_rel_ng to 10%.

Also stop experimental win_chromium_x64_rel_ng.

BUG=731502,731378

Change-Id: I86aaebcafd10634c4146aebd8939cb8a0e969d23
Reviewed-on: https://chromium-review.googlesource.com/1048870Reviewed-by: Andrii Shyshkalov <tandrii@chromium.org>
Reviewed-by: John Budorick <jbudorick@chromium.org>
Reviewed-by: Jao-ke Chin-Lee <jchinlee@chromium.org>
Commit-Queue: Jao-ke Chin-Lee <jchinlee@chromium.org>
Cr-Commit-Position: refs/heads/master@{#556629}

infra/config/branch/cq.cfg

@@ -132,13 +132,7 @@ verifiers {
       }
       builders {
         name: "win10_chromium_x64_rel_ng"
-        equivalent_to { bucket: "luci.chromium.try" percentage: 0 }
-      }
-      builders {
-        # Temporary addition to gather data for LUCI migration.
-        # https://crbug.com/731502
-        name: "win_chromium_x64_rel_ng"
-        experiment_percentage: 2
+        equivalent_to { bucket: "luci.chromium.try" percentage: 10 }
       }
       builders {
         name: "win7_chromium_rel_loc_exp"