Fix memory leaks in HMAC initial packet generation

Fix memory leaks in HMAC initial packet generation

The HMAC leaks are just forgotten frees/deinitialisations.

tls_wrap_control() will sometimes return the original buffer (non
tls-crypt) and sometimes tls_wrap.work, so handling this buffer lifetime
is a bit more complicated.  Instead of further complicating that code
just give our work buffer the same lifetime as the other one inside
tls_wrap.work (put it into per-session gc_arena) as that is also more
consistent.

Second, packet_id_init() allocates a buffer with malloc and not using a
gc_arena, so we need to also manually free it.

Patch v2: add missing deallocations in unit tests of the new workbuf
Patch v3: remove useless allocation of 0 size buffer in
          tls_auth_standalone_init

Found-By: clang with asan
Change-Id: I0cff44f79ee7e3bcf7b5981fc94f469c15f21af3
Signed-off-by: Arne Schwabe <arne@rfc2549.org>
Acked-by: Gert Doering <gert@greenie.muc.de>
Message-Id: <20230315195512.323070-1-arne@rfc2549.org>
URL: https://www.mail-archive.com/openvpn-devel@lists.sourceforge.net/
Signed-off-by: Gert Doering <gert@greenie.muc.de>