[openssl/openssl] 511c49: s_client: Support interactive reconnect command

[Steven Collison]

  Branch: refs/heads/master
  Home:   https://github.com/openssl/openssl
  Commit: 511c49189ef600d41f44cd7c5d204e9ea27b5f48
      https://github.com/openssl/openssl/commit/511c49189ef600d41f44cd7c5d204e9ea27b5f48
  Author: Steven Collison <steven at raycoll.com>
  Date:   2022-10-04 (Tue, 04 Oct 2022)

  Changed paths:
    M apps/s_client.c

  Log Message:
  -----------
  s_client: Support interactive reconnect command

This change adds the 'C' command character to allow a user to drop the
current session and reconnect to the server. It has the same behavior as
the `-reconnect` option except this allows reconnect to be triggered at
an arbitrary point in the session.

The primary use case for this change is to provide a way for the user to
probe a server for TLS1.3 session resumption support. This is not
currently reliably supported by the `-reconnect` option.

Reviewed-by: Dmitry Belyavskiy <beldmit at gmail.com>
Reviewed-by: Paul Dale <pauli at openssl.org>
(Merged from https://github.com/openssl/openssl/pull/18683)