Use assigned machines for ToTiOS{,Device}.

These builders were assigned machines in https://crrev.com/i/3264546.

Bug: 1126929
Change-Id: Ida6f75fa6d562aa4c71533eb36f41480688efcfe
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2406519
Auto-Submit: Garrett Beaty <gbeaty@chromium.org>
Reviewed-by: Michael Moss <mmoss@chromium.org>
Commit-Queue: Michael Moss <mmoss@chromium.org>
Cr-Commit-Position: refs/heads/master@{#806331}

infra/config/generated/cr-buildbucket.cfg

@@ -6745,7 +6745,7 @@ buckets {
       name: "ToTiOS"
       swarming_host: "chromium-swarm.appspot.com"
       swarming_tags: "vpython:native-python-wrapper"
-      dimensions: "builderless:1"
+      dimensions: "builder:ToTiOS"
       dimensions: "cpu:x86-64"
       dimensions: "os:Mac-10.15"
       dimensions: "pool:luci.chromium.ci"
@@ -6777,7 +6777,7 @@ buckets {
       name: "ToTiOSDevice"
       swarming_host: "chromium-swarm.appspot.com"
       swarming_tags: "vpython:native-python-wrapper"
-      dimensions: "builderless:1"
+      dimensions: "builder:ToTiOSDevice"
       dimensions: "cpu:x86-64"
       dimensions: "os:Mac-10.15"
       dimensions: "pool:luci.chromium.ci"

infra/config/subprojects/chromium/ci.star

@@ -1478,6 +1478,7 @@ ci.clang_builder(
 
 ci.clang_builder(
     name = "ToTiOS",
+    builderless = False,
     caches = [xcode_cache.x12a8189n],
     console_view_entry = ci.console_view_entry(
         category = "iOS|public",
@@ -1493,6 +1494,7 @@ ci.clang_builder(
 
 ci.clang_builder(
     name = "ToTiOSDevice",
+    builderless = False,
     caches = [xcode_cache.x12a8189n],
     console_view_entry = ci.console_view_entry(
         category = "iOS|public",