[Bug libstdc++/54005] Use __atomic_always_lock_free in libstdc++ is_lock_free instead of __atomic_is_lock_free

[hp at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=54005

--- Comment #20 from Hans-Peter Nilsson <hp at gcc dot gnu.org> ---
Please allow a couple of days so I can catch up. 
Thanks.