Bump LUCI fuchsia_arm64 to 10% equivalence.

Bug: 776495
Change-Id: Idfc2a6f82fa6bf6934e304c51eb2333659ce6f01
Reviewed-on: https://chromium-review.googlesource.com/993273Reviewed-by: Andrii Shyshkalov <tandrii@chromium.org>
Commit-Queue: John Budorick <jbudorick@chromium.org>
Cr-Commit-Position: refs/heads/master@{#547784}

infra/config/branch/cq.cfg

@@ -87,7 +87,7 @@ verifiers {
       }
       builders {
         name: "fuchsia_arm64"
-        equivalent_to { bucket: "luci.chromium.try" percentage: 0 }
+        equivalent_to { bucket: "luci.chromium.try" percentage: 10 }
       }
       builders {
         name: "fuchsia_x64"