A bunch of Xcode 15 beta 6 tests I've been running on flutter-devicelab-mac-45, have been failing with this error. It seems to be specific to the usage of xcodebuild test and macOS.

The test runner encountered an error (Failed to establish communication with the test runner. (Underlying Error: Couldn’t communicate with a helper application. Try your operation again. If that fails, quit and relaunch the application and try again. The connection to service named com.apple.testmanagerd.control was invalidated: failed at lookup with error 3 - No such process.))

Mac plugin_test_macos
https://chromium-swarm.appspot.com/task?id=6422d254ea7dc010
https://chromium-swarm.appspot.com/task?id=6431d514509ce810

Mac native_ui_tests_macos
https://chromium-swarm.appspot.com/task?id=6431f1a1d54d4310

Mac_arm64 macos_platform_tests master - packages
https://chromium-swarm.appspot.com/task?id=6431f0054f798510

Looks like this has happened in the past: #101721 and it only occurred on arm hosts, but they weren't sure how to fix so they made the tests only run on x86 hosts.

The tests pass for me locally on my arm mac.