ci: Use Cirrus dockerfile cache

ci/lint_run.sh

@@ -0,0 +1,13 @@
+#!/usr/bin/env bash
+#
+# Copyright (c) The Bitcoin Core developers
+# Distributed under the MIT software license, see the accompanying
+# file COPYING or http://www.opensource.org/licenses/mit-license.php.
+
+export LC_ALL=C.UTF-8
+set -o errexit -o pipefail -o xtrace
+
+# Only used in .cirrus.yml. Refer to test/lint/README.md on how to run locally.
+export PATH="/python_build/bin:${PATH}"
+export LINT_RUNNER_PATH="/lint_test_runner"
+./ci/lint/06_script.sh

ci/lint_run_all.sh

@@ -6,7 +6,8 @@
 
 export LC_ALL=C.UTF-8
 
-# Only used in .cirrus.yml. Refer to test/lint/README.md on how to run locally.
+# Only used in .cirrus.yml for stale re-runs of old pull request tasks. This
+# file can be removed in September 2025.
 
 cp "./ci/retry/retry" "/ci_retry"
 cp "./.python-version" "/.python-version"