Function is_current_thread_host_registration_active 

pub fn is_current_thread_host_registration_active(
    registration_high: u32,
    registration_low: u32,
) -> bool

Return whether one exact CurrentThread task- or timer-host registration is still live. The JavaScript package revalidates its process-global marker on every module evaluation so native eviction cannot leave a stale installed bit that permanently suppresses replacement registration.