linux-official should run on assigned bots

Bug: 1072012,1103490
Change-Id: Ieb61903d53e527c4cedee12d099668e96503f68b
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2300838Reviewed-by: Garrett Beaty <gbeaty@chromium.org>
Commit-Queue: Stephanie Kim <kimstephanie@google.com>
Cr-Commit-Position: refs/heads/master@{#788847}

infra/config/generated/cr-buildbucket.cfg

@@ -10651,12 +10651,11 @@ buckets {
       name: "linux-official"
       swarming_host: "chromium-swarm.appspot.com"
       swarming_tags: "vpython:native-python-wrapper"
-      dimensions: "builderless:1"
+      dimensions: "builder:linux-official"
       dimensions: "cores:32"
       dimensions: "cpu:x86-64"
       dimensions: "os:Ubuntu-16.04"
       dimensions: "pool:luci.chromium.ci"
-      dimensions: "ssd:0"
       exe {
         cipd_package: "infra/recipe_bundles/chromium.googlesource.com/chromium/tools/build"
         cipd_version: "refs/heads/master"

infra/config/subprojects/chromium/ci.star

@@ -501,6 +501,7 @@ ci.chromium_builder(
 
 ci.chromium_builder(
     name = 'linux-official',
+    builderless = False,
     # TODO(https://crbug.com/1072012) Use the default console view and add
     # main_console_view = settings.main_console_name once the build is green
     console_view = 'chromium.fyi',