Locking, trylocking, unlocking a destroyed mutex and signalling, broadcasting,
waiting on or destroying a destroyed condition variable threw a C++ exception
into the guest. FreeBSD 11.4 libthr returns EINVAL for all of them (thr_mutex.c
check_and_init_mutex and mutex_unlock_common compare against THR_MUTEX_DESTROYED,
thr_cond.c CHECK_AND_INIT_COND and _pthread_cond_destroy against
THR_COND_DESTROYED). The condition wait path already reported EINVAL for a
destroyed mutex.
Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>
