Extend the watchdog drivertest with notifier ordering, duplicate registration, repeated delivery, unregister, NULL-data, and concurrent registration coverage.
Register the watchdog test when either reset-cause or timeout-notifier support is available. Keep hardware watchdog cases gated by reset-cause support and allow notifier-only simulator builds through both Make and CMake.
Keep test state in the watchdog fixture and notifier blocks so callbacks do not depend on shared notifier state.
Assisted-by: OpenAI Codex
Signed-off-by: hanzhijian <hanzhijian@zepp.com>
