[tls_client] session resumption does not work properly

It doesn't break handshake but resumption never happens. Maybe it's broken just on TLS 1.3, or some similar condition. I tried this with quad-{1,8,9} and it looks the same in verbose log.

We do receive resumption tickets from upstream

[gnutls] (4) HSK[0x1644310]: NEW SESSION TICKET (4) was received. Length 246[496], frag offset 0, frag length: 246, sequence: 0

but never send it on on re-connection (no idea why so far)

[gnutls] (4) EXT[0x1644310]: Preparing extension (Session Ticket/35) for 'client hello'
[gnutls] (4) EXT[0x1644310]: Sending extension Session Ticket/35 (0 bytes)

and thus the session can't resume.

[tls_client] TLS session has not resumed

Tested with latest releases: Knot Resolver 4.3.0 and GnuTLS 3.6.11.1.