[v10.x] tls: expose keylog event on TLSSocket
Backport of #27654.
I had to modify test-tls-keylog-tlsv13.js
to use TLS 1.2 connections as (AFAIK) v10 is not going to support TLS 1.3. I also modified the count from 5 to 1, because TLS 1.2 handshakes only emit 1 keylog event. Should I rename the file to test-tls-keylog-tlsv12.js
?