nptl: Move pthread_rwlock_trywrlock into libc

And __pthread_rwlock_trywrlock as a compatibility symbol.

Remove the unused __libc_rwlock_trywrlock macro.

The symbols were moved using scripts/move-symbol-to-libc.py.

Reviewed-by: Carlos O'Donell <carlos@redhat.com>
Tested-by: Carlos O'Donell <carlos@redhat.com>