https: add client support for TLS keylog events

The keylog event is implemented on TLS sockets, but client HTTPS uses
TLS sockets managed by an agent, so accessing the underlying socket
before the TLS handshake completed was not possible.  Note that server
HTTPS already supports the keylog event because it inherits from the TLS
server.

PR-URL: https://github.com/nodejs/node/pull/30053


Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>
Reviewed-By: Ben Noordhuis <info@bnoordhuis.nl>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>