MAJOR: proxy: enable abortonclose by default on TLS listeners

MAJOR: proxy: enable abortonclose by default on TLS listeners

In the continuity of https://github.com/orgs/haproxy/discussions/3146,
we must also enable abortonclose by default for TLS listeners so as not
to needlessly compute TLS handshakes on dead connections. The change is
very small (just set the default value to 1 in the TLS code when neither
the option nor its opposite were set).

It may possibly cause some TLS handshakes to start failing with 3.3 in
certain legacy environments (e.g. TLS health-checks performed using only
a client hello and closing afterwards), and in this case it is sufficient
to disable the option using "no option abortonclose" in either the
affected frontend or the "defaults" section it derives from.