selftests: tls: add rekey tests

JIRA: https://issues.redhat.com/browse/RHEL-86020

commit 555f0ed
Author: Sabrina Dubroca <sd@queasysnail.net>
Date:   Thu Dec 12 16:36:09 2024 +0100

    selftests: tls: add rekey tests

    Test the kernel's ability to:
     - update the key (but not the version or cipher), only for TLS1.3
     - pause decryption after receiving a KeyUpdate message, until a new
       RX key has been provided
     - reflect the pause/non-readable socket in poll()

    Signed-off-by: Sabrina Dubroca <sd@queasysnail.net>
    Signed-off-by: David S. Miller <davem@davemloft.net>

Signed-off-by: Sabrina Dubroca <sdubroca@redhat.com>

Author: Sabrina Dubroca