luci: update master name for relocated ios-slimnav.

Tbr: justincohen@chromium.org
No-Try: true
Change-Id: Ie1eaf6202192b20bbbc42ca272f44e2c36921d06
Reviewed-on: https://chromium-review.googlesource.com/c/1340909Reviewed-by: John Budorick <jbudorick@chromium.org>
Reviewed-by: Justin Cohen <justincohen@chromium.org>
Commit-Queue: John Budorick <jbudorick@chromium.org>
Commit-Queue: Justin Cohen <justincohen@chromium.org>
Cr-Commit-Position: refs/heads/master@{#608919}

infra/config/global/cr-buildbucket.cfg

@@ -1513,10 +1513,10 @@ buckets {
     builders { mixins: "ios-ci" name: "ios-simulator" }
     builders { mixins: "ios-ci" name: "ios-simulator-full-configs" }
     builders { mixins: "ios-ci" name: "ios-simulator-xcode-clang" }
+    builders { mixins: "ios-ci" name: "ios-slimnav" }
     builders { mixins: "ios-ci" name: "ios-uirefresh-simulator" }
     builders { mixins: "ios-ci" name: "ios-webview" }
     builders { mixins: "ios-ci" mixins: "fyi-ci" name: "ios-simulator-cronet" }
-    builders { mixins: "ios-ci" mixins: "fyi-ci" name: "ios-slimnav" }
     builders { mixins: "ios-ci" mixins: "fyi-ci" name: "ios12-beta-simulator" }
     builders { mixins: "ios-ci" mixins: "fyi-ci" name: "ios12-sdk-device" }
     builders { mixins: "ios-ci" mixins: "fyi-ci" name: "ios12-sdk-simulator" }