The v12.98 release run's build-mac-arm64 job was cancelled with
"The configuration 'macos-14-arm64-us-default' is not supported",
so no mac-arm64 bundle was built. macos-15 is Apple Silicon too and
is what mac.yml already uses. tests/workflowRunnerLabels.test.cjs now
lists macos-14 as retired and checks that build-mac-arm64 asks for a
current Apple Silicon runner.
Thanks to xet7 !