luci: Add iOS slimnav and webview trybots config.

Bug: 903949
Change-Id: Idd49f5d5e04ee522f564625d664616e7687270a8
Reviewed-on: https://chromium-review.googlesource.com/c/1363433
Reviewed-by: John Budorick <jbudorick@chromium.org>
Commit-Queue: Justin Cohen <justincohen@chromium.org>
Cr-Commit-Position: refs/heads/master@{#614028}

infra/config/global/cr-buildbucket.cfg

@@ -3161,6 +3161,8 @@ buckets {
     builders { mixins: "ios-try" name: "ios-simulator-full-configs" }
     builders { mixins: "ios-try" name: "ios-simulator-eg" }
     builders { mixins: "ios-try" name: "ios-simulator-xcode-clang" }
+    builders { mixins: "ios-try" name: "ios-slimnav" }
+    builders { mixins: "ios-try" name: "ios-webview" }
     builders { mixins: "mac-angle-try" name: "mac_angle_compile_dbg_ng" }
     builders { mixins: "mac-angle-try" name: "mac_angle_dbg_ng" }
     builders { mixins: "mac-angle-try" name: "mac_angle_rel_ng" }

infra/config/global/luci-milo.cfg

@@ -4199,6 +4199,12 @@ consoles {
   builders {
     name: "buildbucket/luci.chromium.try/ios12-sdk-simulator"
   }
+  builders {
+    name: "buildbucket/luci.chromium.try/ios-slimnav"
+  }
+  builders {
+    name: "buildbucket/luci.chromium.try/ios-webview"
+  }
   builders {
     name: "buildbucket/luci.chromium.try/mac-rel"
   }