Create a no-op job for mac-arm64-rel-tests on the branches.

chromium-m87/ci/mac-arm64-rel tried to trigger the non-existent builder
chromium-m87/ci/mac-arm64-rel-tests.

Change-Id: I2de27cfd399c75614d1d2d9b78a2edecc80acd41
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2450723
Auto-Submit: Garrett Beaty <gbeaty@chromium.org>
Reviewed-by: Erik Staab <estaab@chromium.org>
Commit-Queue: Erik Staab <estaab@chromium.org>
Cr-Commit-Position: refs/heads/master@{#814004}

infra/config/generated/luci-scheduler.cfg

@@ -11993,6 +11993,16 @@ job {
   acl_sets: "ci-m85"
   noop {}
 }
+job {
+  id: "ci-m85-mac-arm64-rel-tests"
+  schedule: "triggered"
+  acls {
+    role: TRIGGERER
+    granted_to: "chromium-ci-builder@chops-service-accounts.iam.gserviceaccount.com"
+  }
+  acl_sets: "ci-m85"
+  noop {}
+}
 job {
   id: "ci-m85-Win10 Tests x64 1803"
   schedule: "triggered"

infra/config/generators/scheduler-noop-jobs.star

@@ -38,6 +38,11 @@ _NON_BRANCHED_TESTERS = (
     # the branches
     "mac-osxbeta-rel",
 
+    # This tester is triggered by 'mac-arm64-rel', but it is an FYI builder and
+    # not mirrored by any branched try builders and we have limited test
+    # capacity, so we do not need to run it on the branches
+    "mac-arm64-rel-tests",
+
     # These testers are triggered by 'Win x64 Builder', but it is an FYI builder
     # and not mirrored by any branched try builders, so we do not need to run it
     # on the branches (crbug/990885)

infra/config/subprojects/chromium/ci.star

@@ -4136,6 +4136,9 @@ ci.mac_builder(
     os = os.MAC_ANY,
 )
 
+# TODO(estaab) When promoting out of FYI, make tree_closing True and make
+# branch_selector branches.STANDARD_RELEASES, then remove the entry for this
+# builder from //generators/scheduler-noop-jobs.star
 ci.thin_tester(
     name = "mac-arm64-rel-tests",
     builder_group = "chromium.fyi",
@@ -4143,7 +4146,6 @@ ci.thin_tester(
         category = "mac",
         short_name = "a64",
     ),
-    # TODO(estaab): Make this true when promoting out of FYI.
     tree_closing = False,
     triggered_by = [builder_name("mac-arm64-rel")],
 )