Remove A/B testing of LUCI Mac release optional trybots.

TBR=jchinlee@chromium.org

No-Try: True
Bug: 731365, 764174, 764174, 807149
Change-Id: I44dda43c2ead5edbe6801eb6fc11337ad05e399a
Reviewed-on: https://chromium-review.googlesource.com/1006264
Commit-Queue: Andrii Shyshkalov <tandrii@chromium.org>
Reviewed-by: Jao-ke Chin-Lee <jchinlee@chromium.org>
Reviewed-by: Andrii Shyshkalov <tandrii@chromium.org>
Cr-Commit-Position: refs/heads/master@{#549687}

infra/config/branch/cq.cfg

@@ -163,38 +163,6 @@ verifiers {
         name: "mac_chromium_rel_ng"
         equivalent_to { bucket: "luci.chromium.try" percentage: 0 }
       }
-      builders {
-        # The only purpose of this builder here is get data for migrating this
-        # builder to LUCI, see https://crbug.com/731365.
-        # TODO(tandrii): remove this builder once enough data has been
-        # collected.
-        name: "mac_chromium_compile_rel_ng"
-        experiment_percentage: 5
-      }
-      builders {
-        # The only purpose of this builder here is get data for migrating this
-        # builder to LUCI, see https://crbug.com/764174.
-        # TODO(tandrii): remove this builder once enough data has been
-        # collected.
-        name: "mac_chromium_10.10"
-        experiment_percentage: 5
-      }
-      builders {
-        # The only purpose of this builder here is get data for migrating this
-        # builder to LUCI, see https://crbug.com/731360.
-        # TODO(tandrii): remove this builder once enough data has been
-        # collected.
-        name: "mac_chromium_10.12_rel_ng"
-        experiment_percentage: 5
-      }
-      builders {
-        # The only purpose of this builder here is get data for migrating this
-        # builder to LUCI, see https://crbug.com/807149.
-        # TODO(tandrii): remove this builder once enough data has been
-        # collected.
-        name: "mac_chromium_10.13_rel_ng"
-        experiment_percentage: 5
-      }
     }
     buckets {
       name: "master.tryserver.chromium.win"